阅读理解The flood of women into the job market boosted economic growth and changed U.S. society in many ways. Many in-home jobs that used to be done (47) ________ by women — ranging from family shopping to preparing meals to doing (48) ________ work — still need to be done by someone. Husbands and children now do some of these jobs, a (49) ________ that has changed the target market for many products. Or a working woman may face a crushing "poverty of time " and look for help elsewhere, creating opportunities for producers of frozen meals, child care centers, dry cleaners, financial services, and the like. Although there is still a big wage (50) ________ between men and women, the income working women (51) ________ gives them new independence and buying power. For example, women now (52) ________ about half of all cars. Not long ago, many car dealers (53) ________ women shoppers by ignoring them or suggesting that they come back with their husbands. Now car companies have realized that women are (54) ________ customers. It''s interesting that some leading Japanese car dealers were the first to (55) ________ pay attention to women customers. In Japan, fewer women have jobs or buy cars — the Japanese society is still very much male-oriented. Perhaps it was the (56) ________ contrast with Japanese society that prompted American firms to pay more attention to women buyers. WORD BANK [A] scale [F] affordable [K] voluntary [B] retailed [G] situation [L] excessive [C] generate [H] really [M] insulted [D] extreme [I] potential [N] purchase [E] technically [J] gap [O] primarily

阅读理解In the United States, the items on a typical dinner plate have traveled between 1,500 and 2,500 miles to get there. That distance has increased by as much as 25 percent over the last 20 years — an increase that comes with a series of consequences for food, farmers, consumers, local economies and even the global climate. Starting last fall on Tufts'' Medford/ Somerville campus, students had the chance to lower the overall mileage(里程)of their lunches when the dining hall offered apples grown in nearby Topsfield, Mass. Part of the Harvest Food Festival, the "make-your-own-caramel (饴糖) -apple" display featured (特出展示) six different locally grown apple varieties. The popular Tufts Dining Services program was part of ongoing efforts to increase the amount of local produce (农产品) available on Tufts'' campuses. Friedman School Ph.D. student Melissa Bailey is one of those devoted to the cause. Combining her interests in sustainable agriculture and public policy, Bailey took it upon herself to breathe new life into the Tufts Food Awareness Project, a group launched by Tufts graduate students in the 1990s to raise awareness about the environmental, social and health issues connected to food production. "It was a great start, and there had been a lot of student backing and interest," Bailey says. "But when the students graduate, the idea sort of graduates with them if it''s not institutionalized as part of the community." So Bailey joined forces with Julie Lampie, nutrition marketing specialist for Dining Services, in whom she found an enthusiastic ally, and secured a grant from the Tufts Institute for the Environment to pay graduate students Bryanna Millis and Georgia Kayser to work on the project. Together, the team works to raise awareness, solve problems and forge partnerships among the primary players: Tufts'' chefs, major food distributors and local farmers. Bailey and Lampie — who work on the project mainly as a labor of love — also seek to raise awareness among the student body to the point where student demand drives the addition of local produce to Tufts'' menus. On caramel apple night, their outreach (达到的范围) took the form of informational posters about the Connemara House Apple Farm and Guinee family who plant and tend the apple trees. They also described the personal and global benefits of eating locally grown produce. "Of course the students loved making caramel apples, but it also gave them an education," Bailey says. "It''s not up to me to make an ethical appeal to them, but they need to have the information to be able to make an informed choice." From farm to fork What are the benefits of buying local? Obviously, produce making the trip from Topsfield to Medford requires less sossil (化石) fuel to get it from farm to dining hall than apples grown in Washington State. Using less gasoline means reducing the amount of greenhouse gases released into the atmosphere. Shorter trips also require less energy-consuming refrigeration and waste-producing packaging. Some experts estimate that globe-travelling produce can require up to four times as much energy as an equivalent amount of local food and account for four times the greenhouse gas emissions (释放) . Then there''s the amount of energy, water, pesticides and fertilizers that go into raising produce. "If you grow things that are suited to your climate locally," Bailey explains, "you might not need as many of these inputs on the front end to grow things." Since the terrorist attacks of September 11,2001, homeland security experts have even noted that food is more vulnerable to sabotage (破坏) the longer the distance from farm to fork. Recent decades have witnessed the rise of centralized, corporate agriculture; just 10 multinational companies produce more than half of the products available in the average supermarket. That puts the nation''s food supply at greater risk for contamination (污染) — whether intentional or unintentional, as with mad cow disease or E.coli outbreaks. Similarly, if the nation''s transportation systems were ever disabled, many cities and towns would run out of food within a day or two. But as the interest in consuming locally grown produce blossoms, the number of farmers'' markets in the United States has doubled in the last decade. That means a safer and more constant food supply for people lucky enough to live near these 3,100 markets. The Worldwatch Institute estimates consumers are spending some $1 billion annually at local fanners'' markets, pouring that money into their regional economies. A large institution like Tufts buying locally grown produce is a boom to the Massachusetts economy. "The local farms will increasingly benefit, given the volume that we use," Bailey says. "The Guinees love farming apples, and they just saw this as a great community partnership." But even those of us who don''t always think quite so globally still have reason to choose locally grown foods. Many varieties of fruits and veggies have actually been bred for features that will help them survive the trip, not necessarily enhance their flavor. Double-blind taste tests show people simply find local foods fresher, tastier and more appealing. Bailey says that Tufts'' dining staff have been enthusiastic partners, too, rising to the creative challenge of creating menus based solely on what''s locally available. "The chefs Julie [Lampie] works with were great," she says. "They came up with new recipes (食谱) using local butternut squash to make soups." Winter of our discontent With all the attractive reasons to serve local foods in Tufts'' dining halls, there is one, long, cold problem. "The limitation is the winter, basically," Lampie laments. "There is so little available for the majority of the school year, which is really frustrating. The California schools have a huge advantage." In New England, the growing season is short. From June through September, Massachusetts farmers produce everything from apples to watermelons. But after September, only October''s apples, cranberries, cabbages, potatoes and squashes remain for chefs to work with until early veggies like asparagus come up in the spring. "The next step would be twofold: One, to find out what the earliest produce would be and when we could get them, and, two, give the chefs time to prepare," Bailey says. "It''s up to them to integrate the information into their menus, but we need to provide it first." Another issue is food preparation. When foods like potatoes or butternut squash come from national vendors, they arrive in cans pre-peeled (预先削皮的) and cubed (切成方块的) . Lettuce often arrives washed, chopped or shredded. Industry insiders call these prepped and ready-to-go bulk foods "value-added." But neither the local farms nor Tufts has the labor and facilities to process, say, Maine potatoes this way. "For Tufts, the labor costs of having the staff peel hundreds of potatoes," Bailey says, "it''s just not feasible (可行的) ." "That''s something we''re investigating. Maybe it should be a student job to pick up the produce once a week and bring it to the dining facility," says Bailey. "There are obstacles, but I think there are lots of opportunities to overcome those obstacles when you consider the resources we have at Tufts."

阅读理解We all know there exists great void（空白）in the public educational system when it comes tonbsp;26 nbsp;to STEM（Science,Technology,Engineering Mathematics）,One educator named Dori Roberts decided to do something to change this system. Dori taught high school engineering for 11 years.She noticed there was a real void in quality stem education at allnbsp;nbsp;nbsp;27 nbsp;of the public educational system. she said,“I started Engineering for kids (EFK)after noticing a real lack of math, science and engineering programs tonbsp;nbsp;28 nbsp;my own kids in”.She decided to start an after school program where childrennbsp;nbsp;nbsp;nbsp;29 nbsp;nbsp;in STEM-based competitions.The club grew quickly and when it reached 180 members and the kids in the program won several statenbsp;nbsp;30 nbsp;. she decided to devote all her time to cultivating andnbsp;nbsp;31 nbsp;it The global business EFK was born.Dori began operating EFK out of her Virginia home, which she then expanded tonbsp;nbsp;32 nbsp;nbsp;nbsp;recreation centers. Today, the EFK programnbsp;nbsp;nbsp;nbsp;32nbsp;nbsp;nbsp;over 144 branches innbsp;33nbsp;states within the United States and in 21 countries. Sales have doubled from $5 million in 2014 to $10 million in 2015,with 25 new branches planned for 2016. the EFK website states, “Our nation is notnbsp;nbsp;34 nbsp;nbsp;enough engineers. Our philosophy is to inspire kids at a young age to understand that engineering is a greatnbsp;nbsp;nbsp;35 nbsp;.”

阅读理解To understand the marketing concept, it is only necessary to understand the difference between marketing and selling. Not too many years ago, most industries centered primarily on the efficient production of goods, and then relied on "persuasive salesmanship" to move as much of these goods as possible. Such production and selling focuses on the needs of the seller to produce goods and then change them into money. Marketing, on the other hand, focuses on the wants of consumers. It begins with first analyzing the preferences and demands of consumers and then producing goods that will satisfy them. This eye-on-the-consumer approach is known as the marketing concept, which simply means that instead of trying to sell Whatever is easiest to produce or buy for resale, the makers and dealers first try to find out what the consumer wants to buy and then go about making it available for purchase. This concept does not imply that business is benevolent (慈善的) or that consumer satisfaction is given priority over profit in a company. There are always two sides to every business transaction--the firm and the customer--and each must be satisfied before trade occurs. Successful merchants and producers, however, recognize that the surest route to profit is through understanding and meeting the needs of the consumers. A striking example of the importance of meeting the consumers'' needs happened in mid-1985, when Coca-Cola changed the flavor of its drink. The non-acceptance of the new flavor by a significant portion of the public brought about a prompt restoration of the Classic Coke, which was then marketed alongside the new. King Customer ruled!

阅读理解Influenced by movies and popular novels, most people see sharks as people-eating monsters. This is far from the truth. Every year, a few types of sharks injure about 100 people worldwide and kill about 25. Most attacks are by great white sharks, which often feed on sea lions and other marine mammals (海洋哺乳动物). They sometimes mistake human swimmers for their normal prey, especially if they are wearing black wet suits. If you are a typical ocean-goer, your chances of being killed by an unprovoked attack by a shark are about 1 in 100 million. You are more likely to be killed by a pig than a shark and thou sands of times more likely to get killed when you drive a car. Sharks help save human lives. In addition to providing people with food, they are helping us learn how to fight cancer, bacteria (细菌), and viruses. Sharks are very healthy and have aging processes similar to ours. Their highly effective immune system allows wounds to heal quickly without becoming infected, and their blood is being studied in connection with AIDS research. Sharks are among the few animals in the world that almost never get cancer and eye cataracts (白内障). Understanding why can help us improve human health. Chemicals extracted from shark cartilage (软骨) have killed cancerous tumors in laboratory animals, research that someday could help prolong your life. Sharks are needed in the world'' s ocean ecosystem. Although they don'' t need us, we need them. We are much more dangerous to sharks than they are to us. For every shark that bites a person, we kill one million sharks.

阅读理解Lecturing as a method of teaching is so frequently under attack today from educational psychologists and by students that some justification (理由) is needed to retain it. Critics believe that it results in (47) methods of learning which tend to be less effective than those which fully engage the learner. They also (48) that students have no opportunity to ask questions and must all receive the same content at the same pace, that they are exposed only to one teacher''s interpretation of subject matter which will inevitably be prejudiced and that, anyway, few lectures rise above (49) . Nevertheless, in a number of inquiries this (50) assessment of lecturing as a teaching method proves not to be general among students, although they do fairly often comment on poor lecturing techniques. Students (51) lectures which are clear, orderly summary in which basic principles are emphasized, but dislike too (52) digressions (离题) or lectures which consist in part of the contents of a textbook. Students of science subjects consider that a lecture is a good way to introduce a new subject, putting it in its context, or to present material not yet included in books. They also (53) its value as a period of discussion of problems and possible (54) with their lecturer. They do not look for inspiration--this is more (55) mentioned by teachers--but arts students look for (56) in lectures. Medical and dent. al students who have reported on teaching methods, or specifically on lecturing, suggest that there should be fewer lectures or that, at the least, more would be unpopular. WORD BANK [A] praise [F] solutions [K] active [B] originality [G] pessimistic [L] barely [C] passive [H] commonly [M] criticize [D] dullness [I] appreciate [N] strangeness [E] numerous [J] maintain [O] find

阅读理解SURVIVING IN SPACE Motion sickness troubles more than two-thirds of all astronauts upon reaching orbit, even veteran test pilots who have never been airsick. Though everyone recovers after a few days in space, body systems continue to change. Deprived(丧失) of gravity information, a confused brain creates visual illusions. Body fluids surge to chest and head. The heart enlarges slightly, as do other organs. Sensing too much fluid, the body begins to discharge it, including calcium, electrolytes (解液) and blood plasma (血浆). The production of red blood ceils decreases, rendering astronauts slightly anaemic (贫血的). With the loss of fluid, legs shrink. Spinal (脊骨的) discs expand, and so does the astronaut--who may gain five centimeters and suffer backache. Though the .process may sound terrible, astronauts adjust to k, come to enjoy it and seem no worse for wear-at least for short missions such as space shuttle flights that last a week or two. During longer flights, however, physiology enters an unknown realm. As director of Russia''s Institute for Biomedical Problems from 1968 to 1988, Oleg Gazenko watched cosmonauts return from long flights unable to stand without fainting, needing to be carried from the spacecraft. "We are creatures of the Earth,” Gazenko told me. "These changes are the price of a ticket to space". Americans returning from months-long flights on Mir, the Russian space station, also paid the price, suffering losses in weight, muscle mass and bone density. NASA geared up to see how--even if--humans would survive the most demanding of space ventures, a mission to Mars, which could last up to three years. "We don''t even know if a broken bone will heal in space," said Daniel Goldin, NASA''s administrator. To get answers in 1997 Goldin established the National Space Biomedical Research Institute (NSBRI), a panel of experts from a dozen leading universities and research institute. NSBRI will study biomedical problems and by 2010 will present NASA with a "go" or "no go" recommendation on a Mars mission. Jeffrey Sutton, leader of the medical systems team at the NSBRI, has treated the head trauma, wounds, kidney stones and heart rhythm irregularities that one could encounter on the way to Mars. On the spacecraft he envisions, Mars-hound in the year, say, 2018, there may lurk harmful bacteria or carbon monoxide. No problem. The deadly substances will be detected by smart sensors-microprocessors no bigger than a thumbnail--that wander at will through the spacecraft, communicating their finds to a computer that warns the crew. To cope with infection, Sutton plans a factory to make drugs, even new ones, to cope with possible organisms on Mars. Miniature optical and ultrasound devices will image body and brain, while a small X-ray machine keeps track of any bone loss. Smart sensors embedded in clothing will monitor an astronaut''s vital functions. The crew will be able to craft body parts, Sutton says, precisely tooled to an astronaut''s personal anatomy and genome stored in computer memory. Researchers are building artificial liver, bone and cartilage (软骨) tissue right now. Lying in wait beyond the Earth''s atmosphere, solar radiation poses additional problems. The sun flings billions of tons of electrically charged gas into space, relegating Earth''s volcanic eruptions to mere hiccups. Nevertheless, NASA officials are confident the accurate monitoring will warn astronauts of such events, allowing the crew to take refuge in an area where polyethylene (乙烯) shielding will absorb the radiation. A second kind of radiation, cosmic rays from the Milky Way or other galaxies, is a more serious threat--possessing too much energy, too much speed for shielding to be effective. "There''s no way you can avoid them," says Francis Cxueinotta, manager of NASA’s Johnson Space Centre. "They pass through tissue, striking ceils and leaving them unstable, mutilated or dead. Understanding their biological effects is a priority." Another major concern is the psychological health of astronauts. And there''s a new stressor on a three-year Mars Mission-people, other members of the crew. NASA found that the stresses of isolation and confinement can be brought on rapidly simply by giving people few tasks. Mir astronaut Andrew Thomas described how six astronauts were confined in a 12-foot square room for a week. "If you give them little to do, stress can be achieved in a couple of days, says Thomas. Will NSBRI meet Daniel Goldin''s 2010 deadline for a decision on Mars? "Yes, we will perhaps even before. We''re very confident," says Laurence Young, the director of NABRI. Mean while some of NSBRI''s research may bear fruit on Earth. The institute has made one discovery that promises to save many people at risk of sudden cardiac death, usually brought on by a heart rhythm disorder called ventricular fibrillation. This kills 225,000 people in the US each year. Richard Cohen, head of the NSBR1 cardiovascular (心血管的) team, explained that zero gravity may-emphasizing "may"--incite this condition in astronauts. So the team invented a noninvasive diagnostic device that measures extremely tiny changes in heart rhythm. The team found that the device can be used as part of a standard stress test to identify patients at risk. Then pacemaker-like devices can be implanted to regulate the rhythm disorder. "This technology has the potential to save hundreds of thousands of lives," says Cohen. "NASA can be proud." Such discoveries are no accident, says Michael E. DeBakey, a cardiovascular surgeon who has saved many hearts himself. "The key word is research. When I was a medical student and a patient came to the hospital with a heart attack, things were mostly a matter of chance. Today there''s a better than 95 per cent chance of surviving. Now that all comes from research. The unfortunate thing is that there are people, even some scientists, who look at the money that goes to NASA and we could use the money to support our work. That''s very short sighted. The more research that''s done in any area of science, the better off everyone is going to be."

阅读理解Pollution: A Life and Death Issue One of the main themes of Planet under Pressure is the way many of the Earths environmental crises reinforce one another

阅读理解Dr. Henry Lee amazed the world with his outstanding work in forensic (法庭的) science — the investigation and solving of crimes. Born in mainland China but raised in Taiwan, Henry, at the age of 22, was the youngest captain ever in the Taipei Police Department. In 1965, he went to the U.S. and completed his Ph.D. in biochemistry at New York University. Afterwards, he founded the forensic science program at Connecticut''s University of New Haven. This world-renowned crime expert has helped investigate over 6,000 crimes around the world, including war crimes in Bosnia and Croatia. He has also been involved with many high-profile cases, such as the O.J. Simpson trial and John F. Kennedy''s assassination. In 1986, he even solved a Connecticut murder without a body. How did Dr. Lee become such a great success in his field? According to him, as well as possessing a thorough background in science, one needs to employ logic and curiosity, and not give up or be affected by public opinion. "Don''t let anything pressure you to do something unethical," he once claims. Additionally, he emphasized the importance of doing the right thing with the right attitude — a "winner''s attitude." A winner not only takes the initiative and rises to a challenge but believes that obstacles can be overcome and that any mystery can be solved.

阅读理解As soon as it was revealed that a reporter for Progressive magazine had discovered how to make a hydrogen bomb, a group of firearm (火器) fans formed the National Hydrogen Bomb Association, and they are now lobbying against any legislation to stop Americans from owning one. "The Constitution," said the association''s spokesman," gives everyone the right to own arms. It doesn''t spell out what kind of arms. But since anyone can now make a hydrogen bomb, the public should be able to buy it to protect themselves." "Don''t you think it''s dangerous to have one in the house, particularly where there are children around?" "The National Hydrogen Bomb Association hopes to educate people in the safe handling of this type of weapon. We are instructing owners to keep the bomb in a locked cabinet and the fuse (导火索) separately in a drawer." "Some people consider the hydrogen bomb a very fatal weapon which could kill somebody." The spokesman said, "Hydrogen bombs don''t kill people -- people kill people. The bomb is for self-protection and it also has a deterrent effect. If somebody knows you have a nuclear weapon in your house, they''re going to think twice about breaking in." "But those who want to ban the bomb for American citizens claim that if you have one locked in the cabinet, with the fuse in a drawer, you would never be able to assemble it in time to stop an intruder (侵入者)." "Another argument against allowing people to own a bomb is that at the moment it is very expensive to build one. So what your association is backing is a program which would allow the middle and upper classes to acquire a bomb while poor people will be left defenseless with just handguns."

阅读理解Don''t Let Depression Ruin a Good Thing Feeling down? Got the blues? You''re not alone. Everyone gets sad (yes, everyone you''ve ever met). Some people have sad feelings just once in a while, and others may have sad feelings pretty often. More than half of teenagers go through a sad period at least once a month and plenty of younger kids do, too. When you''re in a sad mood, it may feel like it will last forever, but usually feelings of sadness don''t last very long — a few hours, or maybe a day or two. A deeper, more intense kind of sadness that lasts a lot longer is called depression. Each year millions of people are estimated to suffer from depression, a condition so widespread that it has been dubbed (起绰号，叫做) "the common cold of mental illness." Symptoms of Depression Depression is associated with many symptoms and not everyone has the same ones. Some people have many symptoms, while others may only have a few. The symptoms below may signal that you or someone you love may be depressed: --Appearance — sad face, slow movements, absent-minded look --Unhappy feelings — feeling sad, hopeless, discouraged, or listless --Negative thoughts — "I''m a failure." "I''m no good." "No one cares about me." --Reduced activity — "I just sit around and mope." "Doing anything is just too much of an effort." --People problems — "I don''t want anybody to see me." "I feel so lonely." --Guilt and low self-esteem — "It''s all my fault." "I should be punished." --Physical problems — sleeping problems, weight loss or gain, decreased sexual interest, or head aches --Suicidal thoughts or wishes — "I''d better off dead." "I wonder if it hurts to die." Causes of Depression The exact cause of depression remains unclear. The most probable explanation is that it is an imbalance in neurotransmitters (神经传递素) in the brain. But what triggers it in the first place? First, genetic factors. There is growing interest in genetic approaches to understanding a variety of diseases and depression is no exception. Some people certainly seem to be more vulnerable to depression than others and there is growing evidence that some genes could make individuals susceptible (易受感染的) to the disease. Some studies have shown that people who have relatives with depression have a one in four chance of developing it themselves, compared with only one in fourteen for the general population. Secondly, external triggers. In most cases just having these genes is probably not enough to cause depression on its own. Depression can be triggered by a number of factors such as unemployment, bereavement (丧亡), social isolation or even a severe physical illness. Victims of Depression Anyone may suffer from depression, regardless of age, gender, race and belief. It is "normal" for certain people to feel depressed — such as women, older people, employees with work-related stress, or people with chronic illness. Women are more than twice as likely as men to experience depression. Although the reasons for this difference are not known, research suggests that biological differences in women — such as hormonal (荷尔蒙) changes and genetics — may contribute to depression. Additionally, social reasons, such as greater stresses from work and family responsibilities, and even the increased rates of sexual abuse and poverty among women, may lead to higher rates of clinical depression. Depression affects employees at all levels of the corporate ladder. One in every 20 employees experience the illness. An estimated 200 million workdays are lost each year due to employee depression. Depression tends to affect people in their prime working years and if left untreated may last a lifetime. Clinical Depression and Treatment Unfortunately, many employees with depression don''t seek the treatment they need. Some people are embarrassed to get help for depression, or are reluctant to talk about how they are feeling. Others believe that depression will simply go away on its own, and that they should just "tough it out." Such views are simply wrong — like any other medical illness, depression requires professional treatment. Talking to friends, family members can often give you the support needed when going through life''s difficulties. However, for those with clinical depression, such support is no substitute for the care of a health professional. Clinical depression is a serious illness that you cannot treat on your own. Clinical depression is one of the most treatable of all medical illnesses. In fact, more than 80% of people with depression can be treated successfully with medication, psychotherapy or a combination of both. Many people believe that psychological therapies make more sense than the use of antidepressants (抗抑郁病药) — but this ignores the fact that depression is a genuine physical illness. However, the choice of right treatment depends on a variety of factors, such as severity of illness, presenting symptoms, age, etc. Only a qualified healthcare professional can decide if someone has clinical depression. As with many illnesses, if treatment is needed, the earlier it begins the more effective it can be. Furthermore, early treatment decreases the likelihood of recurrence. The commonest forms of psychotherapy aim to help the depressed person replace negative thoughts and attitudes with a more realistic view of themselves and the world about them. Interpersonal psychotherapy focuses more on past and present relationships and examines how they affect the patient''s current functioning. Antidepressant therapies (抗抑郁症药物疗法) began in 1956. Now there is a wide choice of antidepressants available. They are the recognized treatment for all forms of moderate and severe depression regardless of cause. About 70 per cent of patients with depression respond to treatment with antidepressants. Antidepressants are useful and effective, they are not addictive and do not lose efficacy (效力，功效) with continued use. Visit www.depression-screening.org/screeningtest.htm, you can determine whether you have symptoms of depression. The website may help identify any depressive symptoms and determine whether a further evaluation by a medical or mental health professional is necessary. Talk with your doctor or a qualified mental health professional if you think you may have symptoms of clinical depression. With recognition and treatment, depression can be overcome! Life can be enjoyable again!

阅读理解Cholesterol and Heart Disease Do you know your cholesterol level? Many people don''t. A high level of cholesterol in the blood is an important risk factor for heart disease. Some people say that the danger of heart disease is exaggerated. However, heart disease is a main cause of death in developed countries. Every year more than one million Americans have heart attacks, and half of them die. People With heart disease suffer chest pains that make simple activities, such as walking, shaving, or taking a shower, difficult. Research has proven that cholesterol levels are Connected with heart disease. One project in Massachusetts has studied the same group of men and women since 1948. The researchers have found that the people who have high levels of cholesterol have more heart attacks. A natural substance in the blood, cholesterol comes from the liver. The amount of cholesterol is affected by diet and by physical qualities we inherit from our parents. One kind of cholesterol sticks fat to the walls of arteries, making them smaller and finally blocking them. It produces a condition called "hardening of the arteries," which causes heart attacks. With tiny cameras, doctors can see blood circulating through the heart valves. Angiograms (血管造影照片) are x-rays of the heart arteries. They show fat deposits and blockages caused by high cholesterol. Heart disease begins in children as young as 3 years old. It occurs earlier in boys than in girls. Nearly half of teenagers have some fat deposits on their artery walls. Heart disease develops faster if we have high cholesterol levels and also smoke. What is a safe level of cholesterol? Adults have a high risk of heart attack if their cholesterol level is above 240 milligrams per deciliter (1/10 公升) of blood. Below 200 is better. In the Massachusetts study, no one with a cholesterol level below 150 has ever had a heart attack. However, about half of American adults have cholesterol levels above 200. To lower our cholesterol level, we must change our eating habits. Anything that comes from an animal is high in fat and high in cholesterol. The American Heart Association National Cholesterol Education Program says that fat should be no more than 30 percent of our diet. Blood cholesterol levels start to fall after 2 to 3 weeks of following a low-cholesterol, low-fat diet. Dietary changes alone can result in a 10 percent reduction of the average person''s cholesterol level. Aerobic exercise helps, too. Artery blockage can be reduced by as much as 40 percent through changes in diet and amount of exercise. We must educate everyone, including children in elementary schools. We must teach them responsibility for their health through classes in nutrition and aerobic exercise. For example, the smart snack is fruit. Children must be served fruit in the school cafeteria, along with low-fat meals. Schools must send recipes home with the children. Parents must include children in planning and preparing meals and shopping for food. Adults, including persons over the age of sixty five, can lower their cholesterol by 30 or 40 percent. It is never too late to change. One man began his health program when he was seventy- three. By the time he was seventy-seven, he had lowered his arterial blockage from 50 percent to 13 percent and his cholesterol from 320 to 145 without drugs. He went on a vegetarian diet with only 10 percent fat, plus programs to reduce stress and get more exercise. A low-cholesterol diet that cuts out most animal products and high-fat vegetables may be unfamiliar to people. The Heart Association says to use no added fat of any kind. Don’t fry food in oil. Cook it in water, vinegar, or vegetable water. Learn about grains and vegetables. Avoid egg yolks (the yellow part of the egg). Eat potatoes, beans, low fat vegetables, and fruit. People often complain about low-fat diets before they have had time to get used to them. Food can taste good without cream, butter, and salt. You can use olive oil, mustard, fresh herbs, or yogurt instead. A new diet can cause general anxiety, when people feel worried and nervous about what is going to happen. They must learn to deal with the changes in their lives. Sometimes major changes in diet or lifestyle are easier than minor ones because the results are bigger and faster. Fast results encourage us. How can you control the amount of fat in your diet if you eat in restaurants? Restaurants must provide healthy meals that are low in fat, salt, and cholesterol. A diet is a personal thing. Restaurant owners should not make customers feel embarrassed because they want to follow a diet that is good for them. Restaurant owners must learn to give equal service to customers on a healthy diet. Some restaurants have items on the menu marked with a heart to show that they are low in fat, cholesterol, salt, or sugar. A few restaurants serve only these recipes. Heart disease causes one out of every four deaths in East Harlem in New York City. The East Harlem Healthy Heart Program is an educational program. It has 2 goals: to get people to change their diets and to find volunteers to help run educational activities. One way it educates is by street shows. Actors wear costumes and carry big pieces of plastic fat. They entertain so people will listen. Groups of children perform songs and dances that educate people about heart disease and diet. Volunteers lead walking and exercise groups to show people how to begin exercising. Volunteers also stand in supermarkets to suggest healthy food choices to shoppers. The volunteers have shoppers taste two kinds of milk to see which tastes better. Most people are surprised that the low-fat milk tastes better than the whole milk. Shoppers are encouraged to buy low-fat milk instead of whole milk. Education costs money, but it also brings results. In 1983, only 35 percent of the American public knew their cholesterol levels. By 1990, 65 percent of the people had had theirs checked. People feel better if they lower their cholesterol through diet. Healthy people are more confident. They are more attractive to themselves, as well as to others. Their friends stare at them because they look so healthy. We can prevent heart disease by living a healthful lifestyle and eating the right kind of diet. If people don''t do this, two out of three men and women in America will eventually get heart disease.

阅读理解A Mystery in the Lunchbox Hungry? Sit down. We''re having catfish, corn on the cob, baked potatoes and fresh tomatoes. This might turn out to be the most nutritious meal of your life. It might even be the best-tasting dinner you ever had. On the other hand, it might induce an allergic (过敏性的) reaction — even though you are not allergic to any of these foods. Different Opinions about Biotechnology (生物工程) Products Last week''s announcement that the U.S. federal government would impose no special regulations on bioengineered foods, in effect permitting them to be marketed exactly like nature''s own, proclaims a potentially vast change in our food supply. "We will not compromise safety one bit," Vice President Dan Quayle told the press. "And consumers will enjoy better, healthier food products at lower prices." Many specialists in biotechnology agree — in fact, they see consumers around the world benefiting from a new, genetically-engineered green revolution — but critics are urging the government to move ahead more cautiously. "We should have learned from the history of regulating pesticides (杀虫剂) that we never knew the long-term consequences until it was too late," says Ellen Haas, executive director of Public Voice for Food and Healthy Policy, a Washington D.C.-based advocacy group. The Food and Drug Administration maintains that most bioengineered foods present no special safety issues. "We''re saying this is just another plant-breeding technique," says Eric Flamm, deputy director of the FDA''s Office of Biotechnology. How Does Recombination of DNA Work? Here''s how bioengineering works: all cells contain DNA, the long molecule (分子) shaped like a double helix (螺旋). A gene is a swatch (样本) of DNA that controls a certain characteristic of the organism. In the 1970s scientists discovered they could clip off a gene-length swatch from a DNA molecule, and later they learned to affix (固定) it to a different DNA molecule — a cut-and-paste job that became known as gene splicing and results in what''s called recombinant DNA. Immediately, visions of carrots with the flavor of peanut butter began dancing in the imaginations of scientists and food writers alike. But most current experiments are less exotic (异乎寻常的). In many ways the new technology differs little from traditional crossbreeding. One Product of Bioengineered Technology The first example of recombinant DNA in a form suitable for lunch makes its debut (首次露面) next summer: the Flavr Savr tomato. Scientists at Calgene, Inc., a biotech company based in Davis, California, isolated the gene in the tomato that triggers the enzyme (酶) responsible for rotting and rendered it inactive. Rather man having to be picked hard and green for easy shipping, the tomatoes stay on the vine about five days longer than usual. They can be shipped* without refrigeration, which also helps retain flavor, and they''ll resist rotting for more man three weeks, twice as long as their conventionally grown cousins. They aren''t perfect: like other supermarket tomatoes they''re grown with pesticides, they may be waxed, and they still lack the last three to five days of vine-ripening that homegrown tomatoes enjoy. Sampled at Calgene''s headquarters, the Flavr Savr tasted fine; whether consumers still find it worth a dollar more per pound remains to be seen. Developing Pest Resistant Plant Several companies are hard at work on plants that will repel (抵制) pests (害虫). Monsanto, a St. Louis, Missouri, chemical company, expects to put many such products on the market before the end of the decade. The weapon of choice is Bacillus thuringiensis, or BT, a soil-dwelling bacterium (细菌) that creates a protein crystal that is toxic to certain insects but harmless digested by humans. BT has been used for 30 years as an organic pesticide. Scientists can transfer the gene for the toxin into plant cells, and the new plants will produce their own insecticides. Like traditional insecticides, however, these may simply spur the creation of new, more resistant pests. According to Belknap, the solution will be to splice several toxins into a given plant, thus lessening the potential for insects to develop resistance (or inviting the birth of some pretty amazing insects). One Member of the Herbicide (除草剂) Family, and Its Problems Monsanto is also developing herbicide-resistant plants, specifically Roundup-resistant plants. Roundup is one of Monsanto''s most lucrative (获利的) products, a herbicide with sales of a billion dollars a year. It has been recognized as noncarcinogenic (非致癌的) by the Environmental Protection Agency, though it''s toxic to fish. Roundup is used as a weed-killer, but it will kill everything else it touches in the field, so farmers have had to apply it carefully. Now, however, Monsanto can isolate the enzyme in, say, corn, that is fatally vulnerable to Roundup. A corn plant engineered to have twice as much of that enzyme can lose a chunk of it to Roundup and still survive. Critics charge that this technology simply invites fanners to use more Roundup. Good News for the Business but Consumers Are Entitled to Know What They Are Eating It''s not surprising that biotechnology companies were delighted by the FDA''s green light. Environmentalists and other consumer advocates don''t claim the new foods are unsafe by definition, but they do call for tougher scrutiny (监督) than the FDA believes is necessary. "The regulations do a lot more to protect the industry than they do to protect the American consumers, "says Rebecca Goldburg, a senior scientist at the Environmental Defense Fund, an advocacy group. "The public has a right to know what''s in its food." It''s Up to the Biotechnology Industry, not FDA Goldbury and other critics are especially concerned about potential allergens that may be hiding in new products — an orange touched up with a gene from a cherry, for instance. The FDA requires no special testing or labeling unless the new food is substantially different from its traditional version. A new food containing a "common allergen" would also have to be labeled, but as examples of common allergens the FDA suggests only eggs, milk, fish, shellfish, tree nuts, wheat and other legumes. The truth is, almost any food is an allergen (过敏源) to someone. According to the FDA, it''s up to the biotechnology industry to police itself on potential allergens. "If you move a gene, you have to prove it not allergenic or you will have to label it," says Flamm. There Are Better Ways to Produce Food than Using Biotechnological Methods Other critics are uneasy about making such dramatic changes with such speed. "We ought to be testing these changes in large populations over large periods of time," says Greg Drescher, a director of Old-ways Preservation & Exchange Trust, a Boston-based think-tank for food issues. He also questions how useful the new foods really are. "We don''t need to play sorcerer''s (魔法师) apprentice (学徒) with agriculture," he says. "We know how to produce good-tasting food in this country. There are much better ways to eat healthfully than a food supply based on techno-foods." Jeremy Rifkin, the activist who has been fighting biotechnology for years, promises lawsuits and a massive publicity campaigns, and he thinks the public will be on his side. "If people don''t want foods pumped full of hormones (激素) and antibiotics (抗生素), they are never going to go along with genetically-engineered foods," he says. At the very least, these critics may persuade the FDA to require more labeling of the new foods.

阅读理解Because he recognizes the benefits of (47)______ unions for parents, children, and the nation, President Bush hopes to make rebuilding a culture of marriage as a focus of national policy. His current (48)______ requests nearly $300 million to target state-level programs that promote marriage and marriage skills, particularly among (49)______ families. The initial findings of the Fragile Families Survey indicate that not only do most unwed mothers have a strong (50)______ to marry the father of their child, but they believe they have a (51)______ chance of doing so. The President''s proposals would provide the encouragement many of these parents need. It (52)______ requests funds for —Public advertising campaigns on the value of marriage and the skills that increase marital stability and health. —High school education on the value of marriage, relationship skills, and budgeting. —Marriage and relationship skills programs that include parenting skills, financial management, conflict resolution, and job and career advancement for non-married pregnant women and non-married expectant fathers. —Premarital education and marriage skills training for engaged couples and couples interested in marriage. —Marriage (53)______ and marriage skills training programs for married couples. —Divorce (54)______ programs that teach relationship skills. —Marriage mentoring programs that use married couples as role models and mentors in at-risk communities. President Bush''s proposal also would (55)______ the U.S. Department of Health and Human Services, as well as the states, local governments, and private organizations, to better understand how public policy can (56)______ families in which children''s well-being is secure. Word Bank A) verified B) assured C) ensuring D) environmental E) enable F) promote G) fair H) stable I) desire J) reduction K) initiative L) enhancement M) fragile N) specifically O) fair

阅读理解As a bicycle kingdom gearing-up to become an automobile society, China, the world''s third largest car manufacturing base, is facing a serious problem of automobile-related pollution and (47)______ levels of petrol (48)______. China already ranks third among the world''s automobile manufacturing countries, with a voracious domestic demand that has sucked all major automobile manufacturers into the market. (49)______ from the State Environmental Protection Administration show that China will have 33 million automobiles by 2005 and over 131 million by 2020. As the market (50)______, so are serious pollution problems. Vehicles have become the biggest carbon monoxide (一氧化碳) and nitrogen oxide (氧化氮) emitters in big cities like Shanghai, Beijing and Guangzhou. In China''s 14 largest cities, air pollution kills 50,000 newborn babies and causes 400,000 cases of respiratory (呼吸的) illness every year, according to the Ministry of Science and Technology. Not only do vehicles create (51)______ on the environment and human health, a growing automobile society also threatens to (52)______ China''s oil resources. In 2000, vehicles in China consumed 65.6 million tons of oil, one-third of total demand. This expected to rise to 138 million tons annually by 2010 and (53)______ for 43 per cent of the nation''s total oil demand. This figure projected to rise further to 256 million tons by 2020, accounting for 57 per cent of total demand. As a result, China will depend ever more heavily on oil (54)______ — since the country''s domestic oil reserves are quite limited—the nation''s energy security will be greatly (55)______. China''s overall oil demand is (56)______ to be 450 million tons annually by 2020, with imports providing more than half. With overcrowded roads and worsening traffic jams, Chinese cities are urgently seeking solutions to the automobile pollution problem. Word Bank A) affected B) soaring C) overwhelm D) sufficient E) imports F) relationship G) statistics H) account I) stress J) forecasted K) sample L) explodes M) declining N) consumption O) leap

阅读理解PARENTS: Make Your Child A Winner Playing on a soccer team can be an important experience in your child''s life. Participation can help your child physically and personally. However, placing your child on a soccer team does not guarantee a beneficial experience. As a parent you can help your child have a positive experience in playing soccer. The type of support you give to your child can make soccer fun and rewarding or the cause of anxiety and stress. You can motivate your child and help to develop a healthy, positive self-image. Here are some suggestions: Children play soccer to have fun. They also play to learn and improve their skills, to enjoy exciting times, to be with friends, and to stay in shape. In order to maintain or improve your child''s motivation for playing soccer, find out why they like to participate and support their reasons for playing. Success in soccer is more than just winning. Young children equate winning with success and losing with failure. If children win a game, they feel good or worthy. If they lose they feel incompetent or unworthy. This attitude toward winning can be discouraging to children, unless they are always winning. One of your most important roles, therefore, is to help your child keep winning in proper perspective. Try to redefine success in terms of the actual performance or how well your child and the team played. Focusing on the performance rather than the outcome helps keep the game in perspective. Your child may also need guidance in how to deal with success. In winning, two things can happen. Long run success may come so easily that the competitive game loses its challenge. Your child may become complacent and/or arrogant. Conversely the pressure to win may result in a lack of motivation if your child dreads playing in fear of failure. Your child may not be able to perform well and may want to quit. Give encouragement and positive support if this is the case. It is important that you assist your child in understanding their contribution to the team''s overall performance. Winning is fun. Your child needs to know that striving to win is important. Being successful in soccer also means making improvements and striving to do one''s best. You can help develop this winning attitude in your child by encouraging maximum effort during practices and games, rewarding their improvements in mastering skills, and supporting your child to try their best. The will to win is important but the will to prepare to win is of greater value. Losing is inevitable if your child plays soccer. Your child must learn to accept themselves after a loss, this is an important part of participation in the game. Instead of finding excuses it is important for your child to understand the reasons why the team lost. Such reasons may include superior competition, too many mistakes, poor preparation to compete at this level, or maybe the players have a poor attitude. Whatever the reasons your child needs to regroup. Focus on better preparation physically and mentally for training and the next game so he/she can do better next time. This is a valuable lesson. Realistic goals will help your child. Compare current performances with past performances to determine whether your child has been successful. Your child must experience success at a level that demands his/her best effort. When your child''s skill level improves they realize that effort equals success, and will feel a sense of accomplishment. Encourage skill improvements, good plays, and good behavior. Remember to praise effort-not just good performance-this will motivate your child to try hard. The best way to encourage is by praising or with physical response: a pat on the back, thumbs up, or smile. Try to avoid giving money or other material rewards, which may turn play into work and have a negative effect. Mistakes are part of learning the game of soccer. Your child will make plenty of them. When your child makes a mistake, they know. They do not need reminding by you. That''s when they need your encouragement: "Great try!" "Good run!" "You''ll get it next time!" "Super game!". You cannot play the game for your child. Let them make decisions and learn through trial and error. Be patient and assist. If your child displays continual frustration, you can help by giving ideas, or practicing with your child on his/her skills to correct mistakes. Avoid criticizing and punishing your child for mistakes. If you do your child may fear failure. In turn this could lead to stress and worry about not performing well and to dread the possible disapproval of parents, coaches, and teammates. Never be negative to someone else''s child. It hurts the child and parents. It also creates unwanted tension. Negative criticism hinders rather than improves performance for the individual and the team. Fulfill your responsibility. As the number and variety of soccer teams flourish(兴旺), it becomes increasingly necessary for you to investigate the suitability of the different programs for your child. You have the right and responsibility to ask questions before allowing your child to participate on a soccer team. Seek to find a compatible match between the philosophy of the program and the reason why your child wants to participate in soccer. Identifying with your child is perfectly natural. You want your child to be successful. Be careful not to live out your own dreams through your child. Seeing a child''s performance in sports as a reflection of one''s self-worth and success can result in parents setting unrealistically high goals for their child. This can place pressure to perform beyond their capability, a major cause for stress in soccer for children. Be a good role model. Be mindful of your behavior at games. You expect your son or daughter to show good sportsmanship and self-control. As the parent you need to exhibit appropriate behavior yourself, no matter how frustrating it may be to see a poor call or bad play. Let the coach...COACH. During games and practices, leave the coaching to the coach. It confuses players when they receive instructions from more than one source. Your child has the ball, their mind is racing, here comes a defender or two, a split second decision is necessary. Then suddenly from the sidelines: "Shoot!", "Pass!", "Cross!", "Kick it!" "Hustle!". Confused your child hesitates and is stripped of the ball. Then we hear from the sidelines: "Why didn''t you shoot?". Children go out on the field to do their best, and they expect their parents to do the same. Many of the adult leaders are unpaid volunteers. As a parent, you should be realistic in your expectations. However, the adult leaders that your child is associated with should possess some basic characteristics, which are favorable to the development of young people. Adults you would like to see your child imitate.

阅读理解Make the Most of Your Vacation Come home relaxed and refreshed after a more active, yet indulgent trip When many of us take a vacation, more than anything, we seek to relax. We spend long, lazy days on a beach chair or in a hammock and socialize the night away with rum drinks, fancy martinis, and indulgent desserts. Too often, we return home heavier and flabbier than we''ve been since, well, our last vacation. It doesn''t have to be this way. Active vacations are often the most relaxing of all. Wait! It''s all in defining what an active vacation is. We don''t expect you to take up jogging, backpacking, or hang gliding. Rather, we ask the sedentary vacationers among you to spend two to four hours a day doing things. Walking the city streets. Exploring a nature preserve. Going to a zoo. Biking along the ocean. Taking a leisurely rowboat ride. These kinds of activities aren''t just good for your physical health. They improve your mental health, even your spiritual health. And they make vacations memorable and worthwhile. And after all, isn''t that what you want from your vacation? Here are some fresh ideas to make your vacations as pleasurable as they are active and healthy. 1. Make morning time your activity time. Most likely the weather will be friendlier, your energy level higher, and your agenda emptier than later in the day. 2. Reacquaint yourself with sunrises and sunsets. A walk at dawn or dusk is rejuvenation defined. Try to make this a daily ritual of life away from home, and you will guarantee yourself both physical and spiritual replenishment. 3. Get into the water as much as you can. Don''t allow yourself to spend all your time sitting in front of the water. Whether it is the ocean, a swimming pool, or a tree-lined lake, make sure you get into the water for swimming or games or even walking. Heck, merely standing in waist-high water is a good workout , thanks to the action of the water. And you''ll feel so much more alive! 4. Get on the water as much as you can. Paddleboats are a blast. Canoeing is a joy. Rowboats are romantic. Powerboats exhilarating. Sailboats serene. Kayaks pure adventure. Inner tubes can erase 50 years from your attitude in a matter of minutes. Even standing at the rail of a steamboat is exciting. Boats make you feel young, and whether you are propelling them or not, they all bum calories and engage your muscles more than being on dry land. 5. Choose a cruise for your trip. It''s amazing how active you can be being stuck on a boat in the middle of the Atlantic. Most cruise ships offer numerous options for seaworthy exercise. Most ships house pools, golf simulators, rock walls, basketball hoops, fitness centers, jogging and walking areas, and instructor-led fitness classes — and that''s just what''s on board. During your sea and land excursions you can burn calories as you snorkel, swim, hike, scuba dive, and horseback ride. 6. Get out of the car every two hours. Many of us spend a large chunk of our vacations on the road, either getting to and from our destinations, or using the car for sightseeing. But no matter how beautiful the scenery is, great, memorable vacations don''t happen in a car seat. Don''t wait for exhaustion or nature''s call to get you to pull over. Frequently get out and stretch, walk, picnic, shop, visit, and have fun. It''s important for your health and energy, and it makes traveling a lot more active and interesting. Explore New Pastimes 7. Play active games. When most people think of outdoor games, they think of team sports like baseball, football, or volleyball, all of which can be both intimidating and excessively strenuous for grown-ups who stopped playing such things a long time back. So forget about the standard games. All types of fun outdoor games are available today. Start with the old-fashioned ones — badminton, shuffle-board, horseshoes, Wiffle ball, or bocce. Try some new ones too — they make great balls out of Nerf these days, and if you haven''t bought a squirt gun in a while, be prepared for today''s amazing super soakers. Plus all types of new paddle games are available that are easy and fun. Your goal: Play an outdoor game every day while on vacation. 8. Create a silly tournament. Particularly if there are kids on the vacation, it can be a hoot to create your own mini-Olympics. For example, if you use the swimming pool every day, have a daily competition , such as holding your breath underwater, or swimming between people''s legs, or having a big splash contest. Or maybe a weeklong badminton competition. "Silly" is the operative word.— don''t make it serious competition, but just a chance to have active fun in which everyone participates. 9. Play miniature golf. You burn more calories sitting than lying, standing than sitting, and walking than standing. Although miniature golf won''t incinerate fat, it will bum more calories than lying in a hammock. Plus, your kids will have a great time. You probably will too. 10. Beware the food obsession. Let''s be honest: For many of us, vacations are about eating splurges. It''s fresh seafood by the ocean, amazing restaurants in great cities, unlimited breakfast buffets at the hotel, that ice cream/candy/cake/jambalaya that you remember as a child and come back for every few years. This is the stuff of great vacations, and don''t deny yourself these pleasures. Our suggestion: Limit yourself to one food splurge a day. If you do more, the uniqueness and specialness of the splurges fade a-way. And you''ll spend too much time sitting in restaurants—and then sitting some more, recuperating from the overindulgence. 11. Explore on foot. Yes, you can use the Concierge, the travel guides, the map, or the bus tours to get acquainted with a new location. But only by getting out and walking can you truly get the feel of a village, city, resort, or wilderness. We recommend that you plan to spend the first several hours at your vacation destination walking the area. If you are in a city, pick a few restaurants to try while you are walking and make your reservations in person. Be sure to locate the parks, museums, and shopping areas. 12. Fly a stunt kite. If there''s a good wind blowing at your destination, purchase a stunt kite and take it to the beach or other large open area. These kites can be easily assembled and then taken apart, making them perfect for traveling. You''ll give your upper body a great workout as you struggle to control the kite. You may also have to run or walk to keep the kite in the air—or chase it down once it plummets to the earth. 13. Schedule an activity-based vacation. Ready to commit to even more action? Wrap your entire vacation around an activity, such as sailing, skiing, hiking, biking, or exploring. No expertise is necessary — just a willingness to take on a new challenge. Travel agents can hook you up with any number of vacation packages targeted from novice to expert, adolescent to senior, single or whole family. If you have children, look for packages that include excavating dinosaur bones and other anthropological expeditions, or that teach them a new sport. A ski vacation with lessons for different ages and ability levels works beautifully.

阅读理解Highways Early in the 20th century, most of the streets and roads in the U. S. were made of dirt, brick, and cedar wood blocks. Built for horse, carriage, and foot traffic, they were usually poorly cared for and too narrow to accommodate(容纳) automobiles. With the increase in auto production, private turnpike(收费公路)companies, under local authorities began to spring up, and by 1921 there were 387,000 miles of paved roads. Many were built using specifications of 19'' century Scottish engineers Thomas Telford and John Mac Adam (for whom the macadam surface is named) , whose specifications stressed the importance of adequate drainage. Beyond that, there were no national standards for size, weight restrictions, or commercial signs. During World War I, roads throughout the country were nearly destroyed by the weight of trucks. When General Eisenhower returned from Germany in 1919, after serving in the U. S. Army''s first transcontinental motor convoy(车队) ,he noted: "The old convoy had started me thinking about good, two-lane highways, but Germany''s Autobahn or motorway had made me see the wisdom of broader ribbons across the land. " It would take another war before the federal government would act on a national highway system. During World War II, a tremendous increase in trucks and new roads were required. The war demonstrated how critical highways were to the defense effort. Thirteen per cent of defense plants received all their supplies by truck, and almost all other plants shipped more than half of their products by vehicle. The war also revealed that local control of highways had led to a confusing variety of design standards. Even federal and state highways did not follow basic standards. Some states allowed trucks up to 36,000 pounds, while others restricted anything over 7,000 pounds. A government study recommended a national highway system of 33,920 miles, and Congress soon passed the Federal-Aid Highway Act of 1944, which called for strict, centrally controlled design criteria. The interstate highway system was finally launched in 1956 and has been hailed as one of the greatest public works projects of the century. To build its 44,000-mile web of highways, bridge, and tunnels, hundreds of unique engineering designs and solutions had to be worked out. Consider the many geographic features of the country: mountains, steep grades, wetlands, rivers, desserts, and plains. Variables included the slope of the land, the ability of the pavement to support the load, the intensity of road use, and the nature of the underlying soil. Urban areas were another problem. Innovative designs of roadways, tunnels, bridges, overpasses, and interchanges that could run through or bypass urban areas soon began to weave their way across the country, forever altering the face of America. Long-span, segmented-concrete, cable-stayed bridges such as Hale Boggs in Louisiana and the Sunshine Skyway in Florida, and remarkable tunnels like Fort McHenry in Maryland and Mt Baker in Washington, met many of the nation''s physical challenges. Traffic control systems and methods of construction developed under the interstate program soon influenced highway construction around the world, and were invaluable, in improving the condition of urban streets and traffic patterns. Today, the interstate system links every major city in the U. S. and the U. S. with Canada and Mexico. Built with safety in mind, the highways have wide lanes and shoulders, dividing medians or barriers, long entry and exit lanes, curves engineered for safe turns, and limited access. The death rate on highways is half that of all other U. S. roads (0. 86 deaths per 100 million passenger miles'' compared to 1.99 deaths per 100 million on all other roads). By opening the North American continent, highways have enabled consumer goods and services to reach people in remote and rural areas of the country, spurred the growth of suburbs, and provide people with greater options in terms of jobs, access to cultural programs, health care, and other benefits. Above all, the interstate system provides individuals with what they cherish most personal freedom of mobility. The interstate system has been an essential element of the nation''s economic growth in terms of shipping and job creation: more than 75 percent of the nation''s freight deliveries arrive by truck; and most products that arrive by rail or air use interstates for the last leg of the journey by vehicle. Not only has the highway system affected the American economy by providing shipping routes, it has led to the growth of spin-off industries like service stations, motels, restaurants, and shopping centers. It has allowed the relocation of manufacturing plants and other industries from urban areas to rural. By the end of the century there was an immense network of paved roads, residential streets, expressways, and freeways built to support millions of vehicles. The highway system was officially renamed for Eisenhower to honor his vision and leadership. The year construction began he said: "Together, the united forces of our communication and transportation systems are dynamic elements in the very name we bear — United States. Without them, we would be a mere alliance of many separate parts. "

阅读理解Commuter trains are often stuffy and crowded, and they frequently fail to run on time. As if that were not bad enough, physicist Hondon published a paper that gave commuters yet another reason to feel uncomfortable. Dr. Hondon examined mobile-phone usage in enclosed spaces such as railway carriages, buses and lifts, all of which are, in essence, metal boxes. His model predicted that a large number of passengers crowded together, all talking, sending text messages, or browsing the web on their phones, could produce levels of electromagnetic radiation that exceed international safety standards. That is because the radio waves produced by each phone are reflected off the metal walls of the carriage, bus or lift. Enough radiation escapes to allow the phone to communicate with the network, but the rest fills the inside of the carriage with bouncing microwaves. This sounds worrying. However, in a paper published recently, Jaime Ferrer and Lucas Fernández-Seivane from the University of Oviedo in Spain, dispute Dr. Hondou''s findings. They conclude that the level of radiation is safe after all. In their opinion, while each phone produces radiation that bounces around the car, the passengers absorb some of it, which has the effect of reducing the overall intensity. Dr. Hondon''s model, in short, was valid only in the case of a single passenger sitting in an empty carriage with an active mobile phone on every seat. According to Dr. Ferrer and his colleagues, Dr. Hondon overestimated the level of electromagnetic radiation. When one is sitting on a train, they found, the most important sources of radiation are one''s own phone, and those of one''s immediate neighbours. The radiation from these sources far exceeds that from other phones or from waves bouncing around the carriage. And all these sources together produce a level of radiation within the bounds defined by the ICNIRP, the international body that regulates such matters. People concerned about the effects of mobile-phone radiation are unlikely to take much comfort from Dr. Ferrer''s results. Indeed, Dr. Ferrer says he was surprised at how little research has been done in this area. Yet both Dr. Hondon''s results and Dr. Ferrer''s are based on mathematical models. Their models make assumptions about the physical properties of train carriages and their passengers, and both assume that the radiation is uniformly distributed rather than gathered into "hot spots". But if the debate about the safety of mobile phones is to be resolved, there must be less reliance on models, and more emphasis on hard experimental data.

阅读理解We are all conditioned by the way we are brought up. Our values are determined by our parents, and in a larger sense, by the culture in which we live. The Chinese, for example, are not accustomed to the drinking of milk, and may actually become sick if they are compelled to drink a glassful of the beverage. Americans, on the other hand, thrive on milk, although they have many taboos of their own. Some years ago I gave a dinner party during which I served a delicious hors d''oeuvre filled with a meat that tasted somewhat like chicken. My guests wondered what the meat was, but I refused to tell them until they had eaten their fill. I then explained that they had just dined on the flesh of freshly killed rattlesnake. The reaction was nausea--and in some cases violent vomiting. If I had served rattlesnake to a Chinese, he would doubtless had requested a second helping, for in China the dish is considered a delicacy. Another interesting case is the young man I met recently in New York City. An American by birth, he had been removed from his native state of Oregon at the age of six months when his parents went to Japan as missionaries. Orphaned before his first birthday, he was reared by a Japanese family in a remote village. The young man was unmistakably American in appearance, with blond hair and blue eyes. But he had a Japanese style of walking, Japanese facial expressions, and he thought like a Japanese. Though he had learned to speak English fluently, he felt uncomfortable and nut of place in an American city. He soon returned to Japan.