单选题 High Stress May Damage Memory According to a report issued in May 1998, elderly people who consistently high blood levels of the stress hormone. What's more, high levels of cortisol are also associated with shrinking of the hippocampus (海马区), a region of the brain that plays a key role in learning and memory. The findings suggest that even cortisol levels in the normal, "healthy" range can actually accelerate brain aging. The study results "now provide substantial evidence that long-term exposure to adrenal (肾上腺) stress hormones may promote hippocampal aging in normal elderly humans, " write Nada Porter and Phillip Landfield. Cortisol is a hormone releases in response to stress by the adrenal glands(N), which sit on top of the kidneys (肾). Over a 5 to 6 year period, Dr. Sonia Lupine and his colleagues measures 24-hour cortisol levels in 51 healthy volunteers, most of whom were in their 70s. The researchers tested the volunteers' memory on six people in the increasing/high category and five people in the decreasing/moderate group. The groups did not differ in tests of immediate memory, but the increasing/high cortisol group had other memory problems compared with those in the decreasing/moderate group. The researchers also found that the total volume of the hippocampus in those in the increasing/high group was 14% lower than those in the decreasing/moderate group, although there were no differences in other brain regions. The results suggest that "brain aging can be accelerated by levels of adrenal hormones that are not generally regarded as pathological (病态的) and that variation within this normal range is related to variation in the rate of brain aging," write Porter and Landfield. This further suggests that chronic stress may accelerate the worsening of the hippocampus.

单选题 下面有3篇短文，没篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。{{B}}第一篇{{/B}} {{B}} Pool Watch{{/B}} Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are in trouble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds the alarm when it sees someone in danger of drowning. When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard's pager. In trials at a pool in Ancenis, near Nantes, it saved a life within just a few months, says Alistair McQuade, a spokesman for its maker, Poseidon Technologies. Poseidon keeps watch through a network of underwater and overheard video cameras. Al software analyses the images to work out swimmers' trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being east onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around." says McQuade. The software does this by "projecting" a shape in its field of view onto an image of the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory. To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software's "pre-alert" list, says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool's floor texture when viewed from over-head. If so, it alerts the lifeguard, showing the swimmer's location on a poolside screen. The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe. Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools—and he was once an underwater escapologist with a circus. "I say full marks to them if this works and can save lives," he says. But he adds that any local authority spending ￡30,000-plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

单选题Why can't you stop your eternal complaining! A. everlasting B. long C. monotonous D. lengthy

单选题Attitudes to AIDS Now Most people say that the USA is making progress in fighting AIDS,but they don't know there's no cure and strongly disagree that"the AIDS epidemic(流行)is over,"a new survey finds. The findings, released Thursday by the Kaiser Family Foundation, reassure activists who have worried that public concern about AIDS might disappear in light of recent news about advances in treatment and declines in deaths. "While people are very optimistic about the advances, they' re still realistic about the fact that there is no cure",says Sophia Chang,director of HIV programs at the foundation. The Kaiser survey,like a recent USA TODAY Gallup Poll(民意测验),does find that the number of people ranking AIDS as the country's top health problem has fallen. In the Kaiser poll,38% say it's the top concern,down from 44% in a 1996 poll;in the Oallup Poll, 29% say AIDS is No. 1,down from 41%in 1992 and 67% in 1987. Other findings from Kaiser, which polled more than 1,200 adults in September and October and asked additional questions of another 1,000 adults in November: 52% say the country is making progress against AIDS,up from 32% in 1995. 51% say the government spends too little on AIDS. 86% correctly say AIDS drugs can now lengthen lives; an equal number correctly say that the drugs are not cures. 67% incorrectly say that AIDS deaths increased or stayed the same in the past year;24% know deaths fell. Daniel Zingale,director of AIDS Action Council,says,"I'm encouraged that the American people are getting the message that the AIDS epidemic isn't over. I hope the decision-makers in Washington are getting the same message... We have seen signs of complacency(得意). /

单选题Regular visits from a social worker can be of immense value to old people living alone.

单选题Sport or Spectacle? Muhammad Ali is probably the most famous sports figure on earth: he is recognized on every continent and by all generations. The diagnosis of his illness (51) Parlonson's disease after his retirement fuelled the debate about the dangers of boxing and criticism (52) the sport. That, plus his outspoken opposition (53) women's boxing, made people wonder how he would react when one of his daughters decided to take (54) the sport. His presence at Laila's first professional fight, (55) _, seemed to broadcast her father's support. Of course Muhammnad Ali wanted to watch his daughter fight. The ring announcer introduced him as the "the greatest" and as he sat down at the ringside the crowd chanted. Twenty-one-year-old Laila's debut fight was a huge success and there was as much publicity for the fight (56) her father's fights once attracted. (57) , Laila's opponent was much weaker than she was and the fight lasted just 31 seconds. Since then, Laila has won most of her fights by knocking out her opponent. "She knows (58) she's doing, all fight, "said one referee about her. "She knows about moving well. You can see some of her dad's moves." Laila Ali would rather not compare herself (59) her father. She prefers to make her own (60) . Her father supports her decision to enter the sport but he has not spared her the details of what can happen. Laila realizes that her father wants her to understand the (61) possible scenario to see (62) she still wants to go forward with it. She knows she's going to get hit hard at times, that she may get a broken nose or a swollen face, but at least she is prepared for it. Laila's decision to start boxing (63) her father's struggle with the symptoms of Parkinson's disease has of course sparked a mixture of debate and (64) . But Laila is a feisty and determined individual and it is that as much as her famous last name that has made her a magnet for worldwide media attention. Of course, the (65) on the boxing scene of a woman with her family history attracts even more questions about whether women's boxing is sport or spectacle．

单选题The community college is the most rapidly growing segment of higher education in the United States.A. coreB. ideaC. sectorD. problem

单选题According to Dr Pagel，the academic performance of a student will be affected

单选题Natural Food as Choice of Healthy Diet Increasingly, over the past ten years, people—especially young people—have become aware of the need to change their eating habits, because 1 of the food they eat, particularly processed foods, is not good for health. Consequently, there has been a 2 interest in natural foods: foods which do not contain chemical additives and which have not been affected by chemical fertilizers widely used in farming today. Natural foods, for example, are vegetables, fruit and grain 3 have been grown in soil that is rich in organic matter. In simple terms, this means that the soil has been nourished by unused vegetable matter, which provides it 4 essential vitamins and minerals. This in itself is a natural process 5 with the use of chemicals and fertilizers, the main purpose of which is to increase the amount but not the 6 of foods grown in commercial farming areas. Natural foods also include animals which have been allowed to feed and move 7 in healthy pastures. Compare this with what happens in the mass production of poultry: there are battery farms, for example, where thousands of chickens live crowded together in one building and are fed on food which is little better 8 rubbish. Chickens kept in this way are not only 9 as food; they also produce eggs which lack important vitamins. There are other aspects of healthy eating which are now receiving increasing 10 from experts on diet. Take, for example, the question of sugar. This is actually a nonessential food! 11 a natural alternative, such as honey, can be used to sweeten food if this is necessary, we can in fact do 12 it. It is not that sugar is harmful in itself. But it does seem to be additive: the quantity we use has grown steadily over the last centuries and in Britain today each person consumes an average of 200 pounds a year! Yet all it does is to provide us with energy, in the 13 of calories. There are no vitamins in it, no minerals and no fiber. It is significant that nowadays fiber is considered to be an important part of a healthy diet. In white bread, for example, the fiber has been removed. But it is 14 in unrefined flour and of course in vegetables. It is interesting to note that in countries where the national diet 15 large quantities of unrefined flour and vegetables, certain diseases are comparatively rare. Hence the emphasis is placed on the eating of whole meal bread and more vegetables by modern experts on "healthy eating".

单选题{{B}}第三篇{{/B}} {{B}} Early or Later Day Care{{/B}} The British psychoanalyst John Bowlby maintains that separation from the parents during the sensitive "attachment" period from birth to three may scar a child's personality and predispose to emotional problems in later life. Some people have drawn the conclusion from Bowlby's work that children should not be subjected to day care before the age of three because of the parental separation it entails, and many people do believe this. But there are also arguments against such a strong conclusion. Firstly, anthropologists point out that the insulated love affair between children and parents found in modem societies does not usually exist in traditional societies. For example, in some tribal societies, such as the Ngoni, (he father and mother of a child did not rear their infant alone -- far from it. Secondly, common sense tells us that day care would not be so widespread today if parents, care-takers found children had problems with it. Statistical studies of this kind have not yet been carried out, and even if they were, the results would be certain to be complicated and controversial. Thirdly, in the last decade there have been a number of careful American studies of children in day care, and they have uniformly reported that day care had a neutral or slightly positive effect on children's development. But tests that have had to be used to measure this development are not widely enough accepted to settle the issue. But Bowlby's analysis raises the possibility that early day care has delayed effects. The possibility that such care might lead to, say, more mental illness or crime 15 or 20 years later can only be explored by the use of statistics. Whatever the long-term effects, parents sometimes find the immediate effects difficult to deal with. Children under three are likely to protest at leaving their parents and show unhappiness. At the age of three or three and a half almost all children find the transition to nursery easy, and this is undoubtedly why more and more parents make use of child care at this time. The matter, then, is far from clear-cut, though experience and available evidence indicate that early care is reasonable for infants.

单选题His new girlfriend had omitted to tell him that she was married. A. forgotten B. failed C. deleted D. left out

单选题下面的短文有15处空白，请根据短文内容为每处空白确定1个最佳选项。 Once-daily Pill Could Simplify HIV Treatment Bristol-Myers Squibb and Gilead Sciences have combined many HIV drugs into a single pill. Sometimes the best medicine is more than one kind of medicine. Malaria, tuberculosis and HIV/ AIDS, for example, are all treated with {{U}}(51) {{/U}} of drugs. But that can mean a lot of pills to take. It would be {{U}}(52) {{/U}} if drug companies combined all the medicines into a single pill, taken just once a day. Now, two companies say they have done that for people just {{U}}(53) {{/U}} treatment for HIV, the virus, that causes AIDS. The companies are Bristol-Myers Squibb and Gilead Sciences. They have {{U}}(54) {{/U}} a single pill that combines three drugs currently on the market. Bristol-Myes Squibb sells one of them {{U}}(55) {{/U}} the name of Sustiva. Gilead combined the {{U}}(56) {{/U}}, Emtriva and Viread, into a single pill in two thousand four. Combining drugs involves more than {{U}}(57) {{/U}} issues. It also involves issues of competition {{U}}(58) {{/U}} the drugs are made by different companies. The new once-daily pill is the result of {{U}}(59) {{/U}} is described as the first joint venture agreement of its kind in the treatment of HIV. In January the New England Journal of Medicine published a study of the new pill. Researchers compared its {{U}}(60) {{/U}} to that of the widely used combination of Sustiva and Combivir. Combivir {{U}}(61) {{/U}} two drugs, AZT and 3TC. The researchers say that after one year of treatment, the new pill suppressed HIV levels in more patients and with {{U}}(62) {{/U}} side effects. Gilead paid for the study. Professor Joel Gallant at the Johns Hopkins School of Medicine in Baltimore, Maryland, led the research. Glaxo Smith Kine reacted {{U}}(63) {{/U}} the findings by saying that a single study is of limited value. It says the effectiveness of Combivir has been shown in each of more than fifty studies. The price of the new once-daily pill has not been announced. But Gilead and Bristol-Myers Squibb say they will provide it at reduced cost to developing countries. They plan in the next few months to ask the United States Food and Drug Administration to {{U}}(64) {{/U}} the new pill. There are limits to who could take it because of the different drugs it contains. For example, {{U}}(65) {{/U}} women are told not to take Sustiva because of the risk of birth disorders. Experts say more that forty million people around the world are living with HIV.

单选题I am heartily grateful to your help.

单选题A Gay Biologist Molecular biologist Dean Hamer has blue eyes, light brown hair and a good sense of humor. He smokes cigarettes, spends long hours in an old laboratory at the U.S. National Institute of Health, and in his free time climbs up cliffs and points his skis down steep slopes. He also happens to be openly, matter-of-fact gay. What is it that makes Hamer who he is? What, for that matter, accounts for the talents and traits that make up anyone"s personality? Hamer is not content merely to ask such questions; he is trying to answer them as well. A pioneer in the field of molecular psychology, Hamer is exploring the role genes play in governing the very core of our individuality. To a remarkable extent, his work on what might be called the gay, thrill- seeking and quit-smoking genes reflects how own genetic predispositions. That work, which has appeared mostly in scientific journals, has been gathered into an accessible and quite readable form in Hamer"s creative new book, Living, with Our Genes. "You have about as much choice in some aspect of your personality," Hamer and coauthor Peter Copeland write in the introductory chapter, "as you do in the shape of your nose or the size of your feet." Until recently, research into behavioral genetics was dominated by psychiatrists and psychologists, who based their most compelling conclusions about the importance of genes on studies of identical twins. For example, psychologist Michael Bailey of Northwestern University famously demonstrated that if one identical twin is gay, there is about a 50% likelihood that the other will be too. Seven years ago, Hamer picked up where the twin studies left off, homing in on specific strips of DNA that appear to influence everything from mood to sexual orientation. Hamer switched to behavioral genetics from basic research, after receiving his doctorate from Harvard, he spent more than a decade studying the biochemistry of a protein that cells use to metabolize heavy metals like copper and zinc. As he was about to turn 40, however, Hamer suddenly realized he had learned as much about the protein as he cared to. "Frankly, I was bored," he remembers, "and ready for something new." Homosexual behavior, in particular, seemed ripe for exploration because few scientists had dared tackle such an emotionally and politically charged subject. "I"m gay," Hamer says with a shrug, "but that was not a major motivation. It was more of a question of intellectual curiosity—and the fact that no one else was doing this sort of research. "

单选题The desk was a chaos of papers and unopened letters.A. pileB. messC. chainD. mass

单选题Medical Education In 18th. century colonial America, those who wanted to become physicians either learned as personal students from established professionals or went abroad to study in the traditional schools of London, Parisand Edinburgh. Medicine was first taught formally by specialists at the University of Pennsylvania, beginning in 1765, and in 1767 at King's College(now Columbia University), the first institution in the colonies to give the degree of doctor of medicine. Following the American Revolution, the Columbia medical faculty(formerly of King's College) was combined with the College of Physicians and Surgeons, chartered in 1809, which survives as a division of Columbia University. In 1893 the Johns Hopkins Medical School required all applicants to have a college degree and was the first to afford its students the opportunity to further their training in an attached teaching hospital. The growth of medical schools attached with established institutions of learning went together with the development of proprietary(私营的)schools of medicine run for personal profit. most of which had low standards and poor facilities In 1910 Abraham Flexner. the American education reformer, wrote Medical Education in the United States and Canada, exposing the poor conditions of most proprietary schools Subsequently the American Medical Association(AMA)and the Association of American Medical Colleges(AAMC)laid down standards for course content, qualifications of teachers, laboratory facilities, connection with teaching hospitals, and licensing of medical practitioners(开业医师)that survive to this day. By the late 1980s the US and Canada had 142 4. year medical colleges recognized by the Liaison(联络) Committee on Medical Education to offer che M. D. degree；during the 1987-88 academic year,47,262 men and 25,686 women entered these colleges and an estimated 11, 752 men and 5, 958 women were graduated. Graduates, after a year of internship(实习期), receive licenses to practice if they pass an examination given either by a state board or by the National Board of Medical Examiners

单选题Many people have the illusion that wealth is the chief source of happiness.

单选题Many of novelist Carson McCullers" characters are isolated people.

单选题Dining Custom Every land has its own dining custom, and the United States is no exception. Americans feel that the first rule of being a polite guest is to be on time. If a person is invited to dinner at 6:30, the hostess expects him to be there at 6:30 or not more than a few minutes after. Because she usually does her own cooking, she times the meal so that the coffee and meat will be at their best at the time she asks the guest to come. If he is late, the food will not be so good, and the hostess will be disappointed. When the guest cannot come on time, he calls his host or hostess on the telephone, gives the reason, and tells at what time he thinks he can come. As guests continue to arrive, the men in the group stand when a woman enters and remain standing until she has found a chair. A man always rises when he is being introduced to a woman. A woman does not rise when she is being introduced either to a man or a woman unless the woman is much older. When the guests sit down at a dinner table, it is customary for the men to help the ladies by pushing their chairs under them. Even an American may be confused by the number of knives, forks, and spoons beside his plate when he sits down to a formal dinner. The rule is simple, however: use them in the order in which they lie, beginning from the outside. Or watch the hostess and do what she does. The small fork on the outside on the left is for salad, which is often served with the soup. The spoon on the outside at the right is for soup, and so on. Sometimes there is a separate little knife, called a butter spreader, on a small bread-and-butter plate at the left. As the bread is passed, each guest puts his piece on the bread-and-butter plate.

单选题The woman was delighted at the recovery of her stolen jewels.A. angryB. excitedC. irritatedD. pleased