填空题 1. AIDS is the final, life-threatening stage of infection with human immuno-deficiency virus(HIV). AIDS stands for acquired immuno-deficiency syndrome. The name refers to the fact that HIV severely damages the patient's disease-fighting immune system. Cases of AIDS were first identified in 1981 in the United States, but researchers have traced cases to as early as 1969. Millions of AIDS cases have been diagnosed worldwide. 2. AIDS is caused by two viruses that belong to a group called retroviruses. The first AIDS virus was isolated by researchers in France in 1983 and researchers in the United States in 1984. This virus became known as HIV-1. in 1985, scientists in France identified another closely related virus that also produces AIDS. This virus, named HIV-2, occurs mainly in Africa. HIV-1 occurs throughout the world. 3. People infected with HIV eventually develop symptoms that also may be caused by other, less serious conditions. With HIV infection, however, these symptoms are prolonged and often more severe. They include enlarged lymph glands, tiredness, fever, loss of appetite and weight, diarrhea, yeast infections of the mouth and vagina, and night sweats. 4. An HIV-infected person may develop AIDS from 2 to 15 or more years after becoming infected. In children born with HIV infection, this interval is usually shorter. A few people who have been infected with HIV for more than 15 years have not developed any symptoms or suffer only minor symptoms. An infected person can transmit the virus to another person whether or not symptoms are present. Infection with HIV appears to be lifelong in all who become infected. 5. Researchers have identified three ways in which HIV is transmitted: sexual intercourse, direct contact with infected blood, and transmission from an infected woman to her fetus or baby. The most common way of becoming infected is through intimate sexual contact with an HIV-infected person. In the United States, sexual transmission of HIV has occurred mainly among homosexual men, but it is becoming more frequent among heterosexual men and women. 6. People who inject drugs into their bodies can be exposed to infected blood by sharing hypodermic needles, syringes, or equipment used to prepare drugs for injection. Health-care workers can become infected with HIV by coming into direct contact with infected blood. This may occur through injury with a needle or other sharp instrument used in treating an HIV-infected patient. A few patients have become infected while receiving treatment from an HIV-infected dentist. 7. An infected pregnant woman can transmit the AIDS virus to her fetus even if she has no symptoms. Transmission may also occur from an HIV-infected mother to her baby through breast-feeding. 8. Studies indicate that HIV is not transmitted through air, food, or water, or by insects. No known cases of AIDS have resulted from sharing eating utensils, bathrooms, locker rooms, living space, or classrooms.

填空题Retention refers to ______.

填空题下面的短文后有2项测试任务：(1) 第23～26题要求从所给的6个选项中为第2～5段每段选择1个最佳标题；(2) 第27～30题要求从所给的6个选项中为每个句子确定1个最佳选项。 Parkinson's Disease 1. Parkinson's disease affects the way you move. It happens when there is a problem with certain nerve cells in the brain. Normally, these nerve cells make an important chemical called dopamine (多巴胺). Dopamine sends signals to the part of your brain that controls movement. It lets your muscles move smoothly and do what you want them to do. When you have Parkinson's, these nerve cells break down. Then you no longer have enough dopamine, and you have trouble moving the way you want to. 2. No one knows for sure what makes these nerve cells break down. But scientists are doing a lot of research to look for the answer. They are studying many possible causes, including aging and poisons in the environment. Abnormal genes seem to lead to Parkinson's disease in some people. But so far, there is not enough proof to show that it is always inherited. 3. Tremor (颤抖) may be the first symptom you notice. It is one of the most common signs of the disease, although not everyone has it. Tremor often starts in just one arm or leg or only on one side of the body. It may be worse when you are awake but not moving the affected arm or leg. It may get better when you move the limb or you are asleep. In time, Parkinson's affects muscles all through your body, so it can lead to problems like trouble swallowing or constipation (便秘). In the later stages of the disease, a person with Parkinson's may have a fixed or blank expression, trouble speaking, and other problems. Some people also have a decrease in mental skills. 4. At this time, there is no cure for Parkinson's disease. But there are several types of medicines that can control the symptoms and make the disease easier to live with. You may not even need treatment if your symptoms are mild. Your doctor may wait to prescribe medicines until your symptoms start to get in the way of your daily life. Your doctor will adjust your medicines as your symptoms get worse. You may need to take several medicines to get the best results. A. Tips for Patients with the Disease B. Common Treatment for the Disease C. Means of Diagnosis of the Disease D. Typical Symptoms of the Disease E. Possible Causes of the Disease F. Definition of Parkinson's Disease

填空题Napping to a Healthier Heart? 1. Researchers say they have developed a simple test that can tell if a person with heart disease is likely to suffer a heart attack. The test measures levels of a protein in the blood. The researchers say people with high levels of this protein are at high risk of heart attack, heart failure or stroke. 2. Kirsten Bibbins-Domingo of the University of California in San Francisco led the team. For about four years, they studied almost one thousand patients with heart disease. The researchers tested the heart disease patients for a protein called NT-proBNP. Patients with the highest levels were nearly eight times more likely than those with the lowest levels to have a heart attack, heart failure or stroke. 3. The researchers say the presence of high levels of the protein in the blood shows that the heart muscle is under pressure in some way. The study involved mostly men, so the researchers could not say for sure that the results are also true for women. They say the patients with the highest levels of NT-proBNP were older and had other problems like diabetes or high blood pressure. 4. Other researchers say more studies are needed to confirm if knowing the protein levels of a heart patient should affect that person's treatment. They also would like to know if more aggressive treatment could reduce the patient's chance of a heart attack or stroke. The study appeared in the Journal of the American Medical Association. 5. Could a little sleep during the middle of the day reduce the risk of a heart attack? An unrelated study earlier this month in the Archives of Internal Medicine suggests that the answer may be yes. In countries like the United States, afternoon naps are mostly for children. But they are common for adults in Mediterranean countries. And these countries generally have lower rates of heart disease. So scientists in the United States and Greece wondered if naps could play a part. Twenty-three thousand healthy adults took part in the study by Harvard University and the University of Athens. Those who took thirty-minute naps three times a week had a thirty-seven percent lower risk of death from heart problems than people who did not take naps. 6. The researchers say napping may improve heart health by reducing stress. They say the research suggests that naps are especially good for working men. But they say not enough female subjects died during the study to judge the benefits for women.

填空题The Science of Sport 1. At the 2004 Olympic Games in Athens, the Chinese athlete Liu Xiang equaled the world record for the 110 meters hurdles (跨栏) when he ran the race in 12.91 seconds. This record time had been set in 1993 by British sprinter (短跑运动员) Colin Jackson and 9 years went by before another athlete was able to run as fast. 2. Record-breaking in all track events is slowing down and we appear to be moving much closer to the limits of human performance. Nevertheless, every four years, records which were previously thought to be unbeatable are broken. So what"s behind this, never-ending improvement in performance? And how long can we keep breaking records? Is there a limit to human performance or will athletes continue to gain seconds? 3. Most experts agree that it isn"t the athletes" bodies which have changed but the huge advances in sport science which have enabled them to improve their performances. The individual athlete obviously has to have the necessary skill and determination to succeed, but the help of science and technology can be significant. Research has brought a better understanding of the athlete"s body and mind, but the advances in sports equipment technology have also had an important impact on human performance. 4. Scientists have shown that an athlete"s body"s needs vary according to the type of sport. This research has helped top sports people to adapt their training program and diet better to their particular needs. Running the marathon and cycling, for example, are endurance (耐力) sports and require a different parathion (硝苯硫磷脂) to that of a 100-meter sprinter. In some sports, changes in techniques have significantly improved performance. 5. But in any sport, a player"s success or failure results from a combination of both physical and mental abilities. Most coaches use psychological techniques to help their athletes cope with stress and concentrate on their performance. For example, the English football team listens to music in the changing rooms before a game to help the players to relax and not feel so nervous. Before a difficult match, tennis players are encouraged to use visualization (想像) techniques to build confidence and this is almost as good as practice. 6. But as science begins to dominate the sport, are we in danger of losing sight of the heart of the competition, the sporting challenge? What"s more, are all these advantages fair?

填空题What a parent is most concerned with upon the birth of a child is ______.

填空题 A. lack of funding B. many cancer patients C. more lives being saved D. more than five years E. the ultimate answers F. more funding

填空题 Global Warming 1. Smoke is clouding our view of global warming, protecting the planet from perhaps three-quarters of the greenhouse effect. That might sound like good news, but experts say that as the cover diminishes in coming decades, we are facing a dramatic increase of warming that could be two or even three times as great as official best guesses. 2. This was the dramatic conclusion reached last week at a workshop in Dahlem, Berlin, where top atmospheric scientists got together, including Nobel Prize winner Paul Crutzen and Swedish scientist Bert Bolin, former chairman of the UN's Intergovernmental Panel on Climate Change (IPCC). 3. IPCC scientists have suspected for a decade that aerosols (浮质) of smoke and other particles from burning rainforest, crop waste and fossil fuels are blocking sunlight and counteracting the warming effect of carbon dioxide emissions. Until now, they reckoned that aerosols reduced greenhouse warming by perhaps a quarter, cutting increases by 0.2℃. So the 0.6℃ of warming over the past century would have been 0.8℃ without aerosols. 4. But the Berlin workshop concluded that the real figure is even higher—aerosols may have reduced global warming by as much as three-quarters, cutting increases by 1.8℃. If so, the good news is that aerosols have prevented the world getting almost two degrees warmer than it is now. But the bad news is that the climate system is much more sensitive to greenhouse gases than previously guessed. 5. As those gases are expected to continue accumulating in the atmosphere while aerosols stabilize or fall, that means "dramatic consequences for estimates of future climate change", the scientists agreed in a draft report from the workshop. A. Atmospheric Scientists B. The Calculations Made at the Berlin Workshop C. The Previous Calculations of the Effect of Aerosols D. The Scientists' Agreement E. The Authoritative Conclusion F. Greenhouse Gases

填空题My Life at Renda I learned very quickly that being a teaching assistant (TA) at the University of Iowa would be different from being a teacher at Renmin University. (46) Eyes staring, mouths open, students examined my big nose, while was writing my name on the blackboard. At Iowa, when my first classes began, half of my students still hadn't arrived. When very one finally found a seat, ringing cell phones and loud yawns(哈欠)interrupted my opening remarks. It is not that American students were disrespectful. (47) They were, however, far more skeptical than the students I had at Renda. The truth is I couldn't fault them for their skepticism. Undergraduates at large US universities—especially freshmen and sophomores—often have several classes a semester handled by TAs. In some cases, the TA sets the course content. (48) Most have good intentions, but very few are as effective as professors. Every teacher has to confront obstacles to learning—no matter what the culture. Students who talk during lectures, students who cheat, students who question the grade they get for a paper or project dealing with these is all part of the job. (49) . The difference, I think, is that in the US I had to swallow more of my pride. (50) I had a responsibility to teach them, of course, but I had to do so indirectly—as a guide who himself had a few things to learn from the students. A. Back at Renda, I had walked into my first classes feeling like a celebrity. B. In my students' minds, I had little to offer them, except perhaps some sample questions for the mid-term exam. C. In others, the TA works as a grader and discussion leader. D. I encountered these in China, and I faced them in the US. E. On the other hand, being taught by a graduate student is not necessarily bad. F. Most were polite, or at least, indifferent.

填空题Why Do People Shrink? Did you ever see the movie Honey, I Shrunk the Kids? It's about a wacky dad ( who's also a scientist) who accidentally shrinks his kids with his homemade miniaturizing invention. Oops! (1) For older people, shrinking isn't that dramatic or sudden at all. It takes place over years and may add up to only an inch or so off of their adult height (maybe a little more, maybe less). And this kind of shrinking can't be magically reversed, although there are things that can be done to stop it or slow it down. (2) There are a few reasons. As people get older, they generally lose some muscle and fat from their bodies as part of the natural aging process. Gravity (the force that keeps your feet or the ground) takes hold, and the bones in the spine, called vertebrae, may break down or degenerate, and start to collapse into one another. (3) But perhaps the most common reason why some older people shrink is because of osteoporosis. Osteoporosis occurs when too much spongy bone tissue (which is found inside of most bones) is broken down and not enough new bone material is made. (4) Bones become smaller and weaker and can easily break if someone with osteoporosis is injured. Older people — especially women, who generally have smaller and lighter bones to begin with — are more likely to develop osteoporosis. As years go by, a person with osteoporosis shrinks a little bit. Did you know that every day you do a shrinking act, too? You aren't as tall at the end of the day as you are at the beginning. That's because as the day goes on, water in the disks of the spine gets compressed (squeezed) due to gravity, making you just a tiny bit shorter. Don't worry, though. (5) A. They end up pressing closer together, which makes a person lose a little height and become shorter. B. Once you get a good night's rest, your body recovers, and the next morning, you're standing tall again ! C. Over time, bone is said to be lost because it's not being replaced. D. Luckily, there are things that people can do to prevent shrinking. E. The kids spend the rest of the movie as tiny people who are barely visible while trying to get back to their normal size. F. But why does shrinking happen at all?

填空题 阅读下面这篇短文，短文后有2项测试任务：(1)第23～26题要求从所给的6个选项中为第2～5段每段选择1个正确的小标题；(2)第27～30题要求从所给的6个选项中选择4个正确选项，分别完成每个句子。 {{B}} Aspirin -- a New Miracle Drug{{/B}} 1. Using aspirin, an over-the-counter pill on sale in every supermarket without a prescription, to treat serious circulatory disease may seem almost like quackery. But today doctors recognize this drug as a potent compound as important as antibiotics, digitalis and other miracle drugs. 2. In its natural form as willow bark and leaves, this remarkable remedy dates back to Hippocrates2. In 1829 the chemical in the willow tree that can relieve pain and reduce fever was discovered to be salicin. By 1899 the Bayer Company in Germany had marketed a variant, acetylsalicylic acid, under the name of aspirin. 3. Since then, aspirin and compounds containing aspirin have been taken by tens of millions of arthritis patients. As a pain killer aspirin is, according to one study, more effective than all other analgesics and narcotics available for oral use. It also acts on4the body's thermostat, turning down fever. 4. But some of its powers remained unsuspected until recently. In 1950 the late Dr. Craven wrote to a small western medical journal about 400 overweight, sedentary male patients to whom he had given one or two aspirin tablets a day. None had had a heart attack. He enlarged his group to 8,000 and in 1956 reported: "Not a single case of detectable coronary or cerebral thrombosis "and "no major stroke" had occurred in patients who had taken one or two tablets daily for from one to ten years. But his observations were largely ignored. 5. Then Dr. Vane proved that aspirin turned off the body's prostaglandins hormonelike chemicals that can be secreted by every cell. Some potent prostaglandins are harmful compounds that create fever, pain and arthritis. One of them stimulates platelets in the blood to begin forming clots inside arteries. Aspirin blocks this dangerous effect. 6. Vane's finding caused some researchers to recall Craven's 1956 observations, which now had a possible scientific explanation. Numerous studies were begun to find out whether aspirin could indeed inhibit heart attacks and stroke. 7. In 1972, ten US medical institutions began two "double-blind" trials of 303 patients who suffered from transient ischemic attacks (TIAs). Four aspirin tablets a day were given to 153 patients, while placebo tablets were given to 150. Neither patients nor doctors knew which was which. After six months, the patients on aspirin had experienced much fewer TIAs, and fewer strokes and deaths from strokes than the "controls". The results were so conclusive that aspirin has been used for this purpose widely.

填空题1. Humans not only love eating ice cream, they enjoy feeding it to their pets(宠物). Market studies show that two thirds of all dog owners give ice cream ot their dogs. Unfortunately, says William Tyznik, an expert on animal nutrition(营养)at Ohio State University, ice cream is not good for dogs. "It has milk sugar in it, "he says," which dogs cannot digest very well." 2. Bothered by that knowledge but aware of the desire of dog owners to please their companions, Tyznik invented a new frozen treat for dogs that, he says, is more nutritious than ice cream--and as much fun to eat. The product, called Frosty Paws, is made of a liquid by-product(副产品)of cheese and milk with the sugar removed. Frosty Paws also contains refined soy flour, water, vegetable oil, vitamins and minerals. It took Tyznik, who has also invented a horse feed (called Tizwhiz) and another dog food (named Tizbits), three years to perfect the Frosty Paws formulas, and two attempts to commercialise it. After losing ＄ 25,000 trying to market the invention himself, Tyznik sold the rights to Associated Ice Cream of Westerville, Ohio, which makes the product and packages it in cups. 3. Tyznik claims that Frosty Paws has been tested extensively and that "dogs love it". Of 1,400 dogs that have been offered the product, he says, 89 percent took it on the first try. Three out of four preferred it to Milk-Bone or sausages. The product, which will be available in the ice-cream section of supermarkets, comes in packs of three or four cups, costing between ＄ 1.79. 4. What would happen if a human should mistake Frosty Paws for real ice cream? Nothing, says Tyznik. It's harmless, but frankly, he says, it won't taste very good.

填空题Medicine 1 Medicine is the science and art of healing. It is a science because it is based on knowledge gained through careful study and experimentation. It is an art because it depends on how skillfully doctors and other medical workers apply this knowledge when dealing with patients. 2 The goals of medicine are to save lives, to relieve suffering, and to maintain the dignity of ill individuals. For this reason, medicine has long been one of the most respected professions. Thousands of men and women who work in the medical profession spend their lives caring for the sick. When disaster strikes, hospital workers rush emergency aid to the injured. When epidemics threaten, doctors and nurses work to prevent the spread of disease. Researchers in the medical profession continually search for better ways of fighting disease. 3 Human beings have suffered from illness since they first appeared on the earth. Throughout most of this time, they knew little about how the human body works or what causes disease. Treatment was based largely on superstition and guesswork. 4 However, medicine has made tremendous progress in the last several hundred years. Today, it is possible to cure, control, or prevent hundreds of diseases. People live longer than they did in the past as a result of new drugs, machines, and surgical operations. Medical progress in the control of infectious diseases, improvements in health care programs for mothers and children, and better nutrition, sanitation, and living conditions have given people a longer life expectancy. 5 As medicine has become more scientific, it has also become more complicated. In the past, doctors cared for patients almost single-handedly. Patients received treatment at home for most kinds of illness. Today, doctors no longer work by themselves. Instead, they head medical teams made of nurses, laboratory workers, and many other skilled professionals. The care provided by such teams cannot generally be started at home. As a result, clinics and hospitals have become the chief centers for medical care in most countries.A. In ancient tribes, treatment was based largely on superstition.B. Today, extensive knowledge and sophisticated medical techniques make possible the cure, control, and prevention of hundreds of diseases.C. The goals of medicine.D. Control of infectious disease is given as a reason for a longer life.E. School infirmaries appear as a result of increasing complicated medical work.F. Medical care is now provided for patients in hospitals by a medical team consisting of doctors, nurses, and laboratory workers.

填空题 Cloning(克隆): Future Perfect? 1. A clone is all exact copy of a plant or animal produced from any one cell. Since Scottish scientists reported that they had managed to clone a sheep named Dolly in 1997, research into cloning has grown rapidly. In May 1998, scientists in Massachusetts managed to create two identical calves (牛犊) using cloning technology. A mouse has also been cloned successfully. But the debate over cloning humans really started when Chicago physicist Richard Seed made a surprising announcement: "We will have managed to clone a human being within the next two years," he told the world. 2. Seed's announcement provoked a lot of media attention, most of it negative. In Europe, nineteen nations have already signed an agreement banning human cloning and in the US the President announced, "We will be introducing a law to ban all human cloning and many states in the US will have passed anti-cloning laws by the end of the year." 3. Many researchers are not so negative about cloning, they are worried that laws banning human cloning will threaten important research. In March, The New England Journal of Medicine called any plan to ban research on cloning humans seriously mistaken. Many researchers also believe that in spite of attempts to ban it, human cloning will have become routine by 2010 because it is impossible to stop the progress of science. 4. Is there reason to fear that cloning will lead to a nightmare world? The public has been bombarded (轰炸) with newspaper articles, television shows and films, as well as cartoons. Such information is often misleading, and makes people wonder what on earth the scientists will be doing next. Within the next five to ten years scientists will probably have found a way of cloning humans. It could be that pretty soon we will be able to choose the person that we want our child to look like. But how would it feel to be a clone among hundreds, the anti-cloners ask. Pretty cool, answer the pro-cloners (赞成克隆的人).

填空题Ants as a Barometer of Ecological Change At picnics, ants are pests. But they have their uses. In industriesl such as mining, farming and forestry, they can help gauge the health of the environment by just crawling around and being antsy. It has been recognized for decades that ants-which are highly sensitive to ecological change—can provide a near-percent barometer of the state of an ecosystem. Only certain species, for instance, will continue to thrive at a forest site that has been cleared of trees. 1 And still others will move in and take up residence. By looking at which species populate a deforested area, scientists can determine how "stressed" the land is. 2 Ants are used simply because they are so common and comprise so many species. Where mine sites are being restored, for example, some ant species will recolonize the stripped land more quickly than others. 3 Australian mining company Capricorn Coal Management has been successfully using ant surveys for years to determine the rate of recovery of land that it is replanting near its German Creek mine in Queensland. Ant surveys also have been used with mine-site recovery projects in Africa and Brazil, where warm climates encourage dense and diverse ant populations. "We found it worked extremely well there, " says Jonathan Majer, a professor of environmental biology. Yet the surveys are perfectly suited to climates throughout Asia, he says, because ants are so common throughout the region. As Majer puts it. "That"s the great thing about ants. " Ant surveys are so highly-regarded as ecological indicators that governments worldwide accept their results when assessing the environmental impact of mining and tree harvesting. 4 Why not? Because many companies can"t afford the expense or the laboratory time needed to sift results for a comprehensive survey. The cost stems, also, from the scarcity of ant specialists. 5 A. This allowed scientists to gauge the pace and progress of the ecological recovery. B. Yet in other businesses, such as farming and property development, ant surveys aren"t used widely. C. Employing those people are expensive. D. They do this by sorting the ants, counting their numbers and comparing the results with those of earlier surveys. E. The evolution of ant species may have a strong impact on our ecosystem. F. Others will die out for lack of food.

填空题Mergers The most common kind of consolidation today is the merger. (46) With the deregulation of natural gas,the nation's 20 interstate pipeline companies became fearful of cutthroat competition. (47) In 1985 Internorth of Omaha paid $ 2. 3 billion for Houston Natural Gas Corporation,thereby gaining control of the world's longest pipeline. The system connected markets from coast to coast and raised sales to $10 billion. On occasion,mergers have occurred between smaller companies in an industry dominated by a few giant firms. These smaller companies claim that they need to merge to become more efficient and effective in competing against the biggest corporations. (48) The Antitrust Division of the Justice Department has not always agreed with them. Four major waves of mergers have taken place in this country. The first started in 1887, just prior to the passage of the Sherman Antitrust Act,and ended in 1904. It involved such giants as United States Steel and Standard Oil trying to create monopolies in their industries. From the end of World War I until the 1930s,large firms swallowed smaIler firms to create oligopolies. The monopoly has no chance and the oligopoly little chance of succeeding today under present antitrust policy. The third major merger movement began in the 1960s,reached a peak in 1969,and then gradually declined. Many of the acquisitions involved giant firms in one industry buying up large companies in totally unrelated industries. Such mergers are called conglomerate mergers (49) Mergers in the last ten years were in the thousands. More important is the value of the transactions,which has risen sharply. The number of mergers and acquisitions apply only to those valued at $100 million or more. The petroleum industry had mergers and acquisitions valued at close to $ 80 billion between 1981 and 1984. (50) A. Some felt that they could increase their efficiency and improve their market flexibility by merging.B. They maintain that such action increases competition instead of reducing it.C. Other industries experiencing large takeovers were banking and finance,insurance,mining and mineral, and processed foods.D. Fierce competition on the international market results in combinations of small firms.E. A classic example is Mobil Oil Corporation's purchase of the huge retail chain Montgomery Ward & Company.F. A merger occurs when two or more companies get together to form one company.

填空题 阅读下面的短文，文章中有5处空白，文章后面有6组文字，请根据文章的内容选择5组文字，将其分别放回文章原有位置，以恢复文章原貌。 {{B}} Who is Uncle Sam?{{/B}} "Uncle Sam", of course, stands for the United States. It is the nickname(绰号) of the country. It is hard to believe that this nickname arose quite by accident and there was a man called "Uncle Sam" {{U}}(46) {{/U}}. The man was called Uncle Sam Wilson. He was born in Arlington, Massachusetts (麻萨诸塞州), September 13,1766. At the age of 14 Sam joined the American Revolutionary War, and served in the army under George Washington until the end of the war. He then moved to Troy New York State and began a meat-packing business in the year 1812 war broke out between the United States and Great Britain. {{U}}(47) {{/U}}. Among them was Governor Daniel Tompkings of New York State. He noticed the capitalized letters EAUS on the packages of meat and asked what they stood for. A workman replied that EA stood for Elbert Anderson, the businessman for whom Sam was working. {{U}}(48) {{/U}}. In May 1813, this story appeared in a newspaper published in New York. {{U}}(49) {{/U}}. By the end of the War of 1812, "Uncle Sam" had come to symbolize (象征)the character of the nation and the government. {{U}}(50) {{/U}}.A And he added jokingly that US (actually it was the short form for the United States stood for Uncle Sam Wilson.)B However, not many people have ever heard of such a man. Not even most young Americans.C He did his bit to support the American army.D In 1961 the US Congress(国会) made a decision that "Uncle Sam" is the America's national symbol.E On October 2 that year, a group of visitors came to Sam's meat-packing plant.F Since Uncle Sam was an example of a hard-working man and a lover of America, the idea of "Uncle Sam" as the name for this kind of man became well-known rapidly.

填空题Volts from the Sky 1 Lightning has caused awe and wonder since old times. Although Benjamin Franklin demonstrated lightning as an enormous electrical discharge more than 2030 years ago, many puzzles still surround this powerful phenomenon. 2 Lightning is generated when electrical charges separate in rain clouds, though processes are still not fully understood. Typically, positive charges build at the cloud top, while the bottom becomes negatively charged. In most instances of cloud-to-ground lightning, the negatively charged lower portion of the cloud repels negatively charged particles on the ground's surfaces, making it become positively charged. The positive charge on the ground gathers at elevated points. 3 A flow of elections begins between the cloud and earth. When the voltage charge becomes large enough, it breaks through the insulating barrier of air, and electrons zigzag earthward. We see the discharge as lightning. 4 Lightning can occur within a cloud, between clouds, or between clouds and the ground. The first variety, infra-cloud lightning, is the most frequent but is often hidden from our view. Cloud-to-ground lightning, making ups about 20 percent of lightning discharges, is what we usually see. Lightning comes in several forms, including sheet, ribbon, and ball. Intra-cloud lightning can illuminate a cloud so it looks like a white sheet, hence its name. When cloud-to-ground lightning occurs during strong winds, they can shift the lightning channel sideways, so it looks like a ribbon. The average lightning strike is more than 3 miles long and can travel at a tenth of the speed of light. Ball lightning, the rarest and most mysterious form, derives its name from the small luminous ball that appears near the impact point, moves horizontally, and lasts for several seconds. 5 Thunder is generated by the tremendous heat released in a lightning discharge. Temperatures near the discharge can reach as high as 50,000[o]F within thousandths of a second. This sudden heating acts as an explosion, generating shock waves we hear as thunders. 6 About 2,000 thunderstorms are occurring in the world at any time, generating about 100 lightning strikes every second, or 8 million daily. Within the United States, lightning strikes are estimated at 20 million a year, or about 22,000 par day. You have a 1-in-600,000 chance of being struck by lightning during your lifetime. Lightning can strike twice or more in the same spot. The Empire State Building in New York is struck by lightning about two dozen times annually. 7 You can measure how far you are from a lightning strike by counting the seconds between viewing the flash and hearing the bang, and then dividing by five. This approximates the mileage.A. Cloud-to-ground Lightning Occurring in the USB. Types of LightningC. Cause of LightningD. Differences Between Thunder and ThunderstormE. Frequencies of Thunderstorms Occurring in the World and the USF. Shock Waves as Thunder

填空题Leslie's 10 - year - old sister Aubyn asked how many foster children there were in the area and found out that there were 300. Most of those children had to carry their things from place to place in plastic or paper bags. Leslie's concern and the thought of those 300 children inspired young Aubyn to take action. Aubyn decided to ask people to donate their old suitcases to these foster children. ______ But after a few weeks, she had not received any donations.A. Charles and Isaac Meadows, ages 14 and 11, and Welland Burnside, Aubyn's 8 - year - old brother, got involved with the project in its early stages.B. She began making and hanging posters, speaking at churches, and asking other children for help.C. Aubyn inspired other kids to help with the cause too.D. Eventually, Aubyn's humanitarian efforts were noticed by the media.E. By its sixth year, the little organization reached international status, having chapters in more than ten countries.F. That's how Aubyn Burnside founded her program, suitcases for Kids.

填空题The tension between a yearning for a more relaxed lifestyle and the knowledge that the benchmark for success has been raised in recent years weighs heavily on the minds of the townspeople. ______ They are afraid that any gap in their children's physical or intellectual development might mean they won't be admitted to the" right" universities and won't succeed in a more and more competitive world.A. Younger students took "Save the Date for Me" fliers home to their parents.B. Nevertheless, it seems that Family Night worked, at least to a point.C. And schools and clubs agreed to cancel homework and meetings so families could relaxand be together.D. But sadly, few families believe that one night will change their lives.E. For a few months before Fami Night, a committee of volunteers worked hard to spread the word.F. Parents feel obligated to make sure their children are prepared to survive in today's high - pressure work environment.