单选题Step Back in Time Do you know that we live a lot longer now than the people who were born before us? One hundred years ago the average woman lived to be 45. But now, she can live until at least 80. One of the main reasons for people living longer is that we know how to look after ourselves better. We know which foods are good for U.S. and what we have to eat to make sure our bodies get all the healthy things they need. We know why we sometimes get ill and what to do to get better again. And we know how important it is to do lots of exercise to keep our hearts beating healthily. But in order that we don't slip back into bad habits, let's have a look at what life was like 100 years ago. Families had between 15 and 20 children, although many babies didn't live long. Children suffered from lots of diseases, especially rickets (佝偻病) and scurvy (坏血病), which are both caused by bad diets. This is because many families were very poor and not able to feed their children well. Really poor families who lived in crowded cities like London and Manchester often slept standing up, bending over a piece of string, because there was no room for them to lie down. People didn't have fridges until the 1920s. They kept fresh food cold by storing it on windowsills (窗台板) , blocks of ice, or even burying it in the garden. Some children had to start work at the age of seven or eight to earn money for their parents. If you had lived 100 years ago, you might well be selling matchsticks (火柴杆) (a job done by many children) or working with your dad by now.

单选题When apprentices in colonial America satisfactorily completed their training periods each received two sets of {{U}}apparel{{/U}} as a graduation gift.

单选题John {{U}}talked over{{/U}} the new job offer with his wife. A. discussed B. mentioned C. accepted D. rejected

单选题I hope that I didn't do anything absurd last night.

单选题Evolution has hardly changed the horseshoe crab over millions of years.

单选题Although fish have no vocal organs,they still are able to make noises.

单选题After 1850,various states in the United States began to pass compulsory school attendance laws.A. harshB. diversifiedC. mandatoryD. complicated

单选题The little girl grasped her mother"s arm as she crossed the street.

单选题{{B}}第三篇{{/B}} {{B}} Problems of the Elderly{{/B}} Gerontologists (老年人问题学者) study how old people are treated within a society and how the elderly deal with the inevitable problems of aging, particularly those involving health and income. Health problems include normal losses in hearing, eyesight, and memory, and the increased possibility of chronic(慢性的)diseases. These losses are gradual and proceed at different rates for each individual. In general, the health of old people today is better than that of earlier generation — a condition that is likely to improve Still further as more people receive better medical care throught their lives. Because most old people are no longer in the labor force, a steady source of income is necessary. Systems of pensions and benefits are characteristic of industrial societies. One example is Social Security in the U.S., which is now increased automatically as the cost of living rises, thus reducing somewhat the effect of inflation. Although the income of retired people is about half that of working people, most manage to remain financially independent. Income needs and health are what people consider most when they decide whether to re-tire or not. Putting an end to the limit on the retirement age is not expected to cause many workers to stay on the job if they can afford to retire. The need to relieve strains on the Social Security system, however, has led to legislation that gradually raises the age at which people can get full benefits. This might force them to work longer in the future. Elderly people themselves often display high spirits, satisfaction with life, and feelings of self-worth. The important factors are health and income. The task of modem societies is to ensure that the aged have their basic needs met and that they can continue to function in the community.

单选题 A Miracle Cancer Cure Unless you have gone through the experience yourself, or watched a loved one's struggle, you really have no idea just how desperate cancer can make you. You pray, you rage, you bargain with God, but most of all you clutch at any hope, no matter how remote, of a second chance at life. For a few excited days last week, however, it seemed as if the whole world was a cancer patient and that all humankind had been granted a reprieve. Triggered by a front-page medical news story in the usually reserved The New York Times, all anybody was talking about on the radio, on television, on the Internet, in phone calls to friends and relatives—was the report that a combination of two new drugs could, as The New York Times put it, cure cancer in two years. In a matter of hours patients had jammed their doctors' phone lines begging for a chance to test the miracle cancer cure. Cancer scientists raced to the phones and fax lines to make sure everyone knew about their research too, generating a new round of headlines. The time certainly seemed ripe for a breakthrough in cancer. Only last month scientists at the National Cancer Institute announced that they were halting a clinical trial of a drug called tamoxifen—and offering it to patients getting the placebo—because it had proved so effective at preventing breast cancer (although it also seemed to increase the risk of uterine cancer). Two weeks later came The New York Times' report that two new drugs can shrink tumors of every variety without any side effects whatsoever. It all seemed too good to be true, and of course it was. There are no miracle cancer drugs, at least not yet. At this stage all the drug manufacturer can offer is some very interesting molecules, and the only cancers they have cures so far have been in mice. By the middle of last week, even the most breathless TV talk-show hosts had learned what every scientist already knew: that curing a disease in lab animals is not the same as doing it in humans. "The history of cancer research has been a history of curing cancers in the mouse," Dr. Richard Klausner, head of the National Cancer Institute, told the Los Angles Times. "We have cured mice of cancer for decades—and it simply didn't work in people."

单选题The girl is Ugazina/U at herself in the mirror.

单选题Relieving the Pain "Exercise may be the best treatment of chronic pain," say doctors at a new clinic for dealing with pain. "People with chronic pain need to stop lying around, go out more, and start exercising." The instinctive reaction to acute pain is to stop moving and to try to protect the source of pain. But it seems that this is often not productive, especially in the case of back pain. Back pain, after headaches and tiredness, has become the third most common reason for people to visit their doctors. Painful backs now account for millions of days off work. Lumbar (腰部的) pains are partly the price humans pay for taking their forelimbs off the ground, but they are made worse by a sedentary (久坐不动的) lifestyle. Lack of exercise slowly decreases the flexibility and strength of muscles, so that it is more difficult to take pressure off the site of pain. Exercise is essential It releases endorphins (内啡肽), the body"s "feel-good" chemicals, which are natural painkillers. In fact, these are so important that researchers are now looking for drugs that can maintain a comfortable level of endorphins in the body. Most people who go to a family doctor complaining of pain are prescribed pain-killing drugs rather than exercise. Since finding the cause of backache is not so easy, doctors frequently do not know the precise cause of the discomfort, and as the pain continues, sufferers end up taking stronger doses or a series of different drugs. "It"s crazy," says Dr. Brasseur, a therapist at the International Association for the Study of Pain. "Some of them are taking different drugs prescribed by different doctors, I"ve just seen a patient who was taking two drugs which turned out to be the same thing under different names." A generation of new pain clinics now operates on the basis that drugs are best avoided. Once patients have undergone the initial physical and psychological check up, their medication is cut down as much as possible. Taking patients off drugs also prepares them for physical activity. In some pain-relief clinics, patients begin the day with muscle contraction and relaxation exercises, followed by an hour on exercise bikes. Later in the day, they practice tai chi (太极), self-defense, and deep thought. This compares with an average of two-and-a-half hours" physiotherapy (理疗) a week in a traditional hospital program. "The idea is to strengthen and to increase long-lasting energy, flexibility, and confidence," explains Bill Wiles, a consultant pain doctor in Liverpool. "Patients undergoing this therapy get back to work and resume healthy active lifestyles much sooner than those subjected to more conservative treatment."

单选题What Is Market? The word market is used in a number of ways. There is a stock market and an automobile market,a retail market for furniture and a wholesale market for furniture. One person may be going to the market:another may plan to market a product. What,then is a market? A market may be defined as a place where buyers and sellers meet, goods or services are offered for sale. and transfers of ownership occur. A market may also be defined as the demand made by a certain group of potential buyers for a good or service. For instance,there is a farm market for petroleum products. The terms market and demand are often used interchangeably; they may also be used jointly as market demand. These definitions are not sufficiently precise to be useful to us here. For business purposes we define a market as people or organizations with wants (needs) to satisfy,money to spend, and the willingness to spend it. Thus in the market demand for any given product or service, there are three factors to consider-people or organizations with wants(needs), their purchasing power,and their buying behavior. We shall employ the dictionary definition of needs:the lack of anything that is required, desired,or useful. We do not limit needs to the narrow physiological requirements of food, clothing and shelter essential for survival. In our discussion the words needs and wants are used synonymously and interchangeably. In a strict interpretation,however,needs would refer to such basic physiological requirements as food,clothing,and shelter, while wants would be non-basic preferences. However,in our affluent society,little is to be gained by trying to differentiate between the two. Many of us would see as needs some items that are far beyond food, clothing, and shelter.

单选题The Klondike was the {{U}}scene{{/U}} of one of the biggest gold rushes the world has ever known. A. location B. view C. event D. landscape

单选题 Souped-up(效力增强了的) enzymes that flush poisons out of cells more efficiently than their natural counterparts(对应的人或物) could alleviate some of the severe side effects of chemotherapy and so improve the chances of curing cancers. Many anticancer drugs attack tumor cells because they divide more rapidly than heathy cells. But some vital healthy cells also divide faster thanormal, and these are destroyed as well. The most vital cells caught in the chemical cross-fire are those made in the bone marrow(骨髓). Under normal circumstances, these mature into platelets(血小板), which are vital for wound-healing, and white blood cells that fight infections. If levels of these cells fall, patients become dangerously vulnerable to infection and can suffer such severe internal bleeding that treatment has to be stopped. Surviving cancer cells can then re-grow and reduce the effectiveness of the therapy. Bill Fehl and his colleagues at the University of Wisconsin Medical School have engineered an enzyme that could make bone marrow cells resistant to the cancer drugs, so higher doses can be given and side effects reduced. The idea is to take healthy bone marrow cells from patients before they begin chemotherapy, then equip these cells with the genes that make the enzyme drug-resistant. When returned to the patient, the improved bone marrow cells could then withstand heavy doses of the drugs. The natural version of the enzyme—called glutathione Stransferase(谷胱甘肽S转移酶) —is produced mainly in the liver and catalyses(催化) the breakdown of compounds that might otherwise damage DNA in cells. GST also neutralizes(中和) the toxic breakdown products of anticancer drugs, which makes it suitable for protecting bone marrow cells. But natural GST does not work efficiently enough to avoid being swamped by high doses of drugs. GST catalyses a reaction between potentially toxic compounds and glutathione—a peptide (肽) produced in almost all cells of the body. The GST molecule has a cavity, or "active site", where the two molecules are brought close enough to react. This neutralizes the toxin, which passes into the blood to be excreted in the patient's urine. Using machines for synthesizing(结合,使合成)DNA, Fehl and his colleagues made thousands of "scrambled" versions of the parts of the GST gene that make the active site of the enzyme. They inserted these scrambled genes into Escherichia coll. By exposing the bacteria to increasing quantities of the anticancer drug, mechlorethamine(氮芥), Fehl screened out the ones most tolerant to the drug. "By this method, we made enzymes 30 times as efficient as the natural one," says Fehl. In other words, it took 30 times as much drug to kill the bacteria. Fehl has already exposed mice carrying copies of the doctored gene to known carcinogens(致癌物) to see how efficient the gene is at mopping up the toxins. The more efficient it is, the less damage the toxins do and fewer tumors should appear. "We anticipate a significant reduction (in the number of cancers) in the group carrying the gene, "says Fehl, who is still analyzing the results. Fehl's team has applied for a patent covering the technique, and hopes to develop treatments with Systemix, a company based in Palo Alto, California. Brian Ketterer, who heads the Cancer Research Campaign's molecular toxicology group in London, says Fehl's work could be important. But he warns that the proposed strategy would not protect cells lining the gut from chemotherapy drugs.

单选题We must run, Uotherwise/U we will be late.

单选题Jack eventually overtook the last truck.

单选题Is ￡ 20 {{U}}sufficient{{/U}} for the expenses of your journey?

单选题He is determined to consolidate his power.

单选题 阅读下面这篇短文，短文后列出7个句子，请根据短文的内容对每个句子做出判断。 {{B}}Most Adults in US Have Low Risk of Heart Disease{{/B}} More than 80 percent of US adults have a less than 10-percent risk of developing heart disease in the next 10 years, according to a report in the Journal of the American College of Cardiology. Just 3 percent have a risk that exceeds 20 percent. "I hope that these numbers will give physicians, researchers, health policy analysts, and others a better idea of how coronary heart disease is distributed in the US population," lead author Dr. Earl S. Ford. from the Centers for Disease Control and Prevention in Atlanta, said in a statement. The findings are based on analysis of data from 13,769 subjects, between 20 and 79 years of age, who participated in the Third National Health and Nutrition Examination Survey from 1988 to 1994. Overall, 82 percent of adults had a risk of less than 10 percent, 15 percent had a risk that fell between 10 to 20 percent, and 3 percent had a risk above 20 percent. The proportion of subjects in the highest risk group increased with advancing age, and men were more likely than women to be in this group. By contrast, race or ethnicity had little effect on risk distributions. Although the report suggests that most adults have a low 10-year risk of heart disease, a large proportion have a high or immediate risk, Dr. Daniel S. Berman, from Cedars-Sinai Medical Center in Los Angeles, and Dr. Nathan D. Wong, from the University of California at Irvine, note in a related editorial. Aggressive treatment measures and public health strategies are needed to shift the overall population risk downward, they add.