单选题A Dolphin and an Astronomer One day in 1963, a dolphin named Elvar and a famous astronomer, Carl Sagan，were playing a little game. The astronomer was visiting an institute which was looking into the way dolphins communicate with each other. Sagan was standing on the edge of one of the tanks where several of these friendly, highly intelligent creatures were kept. Elvar had just swum up alongside him and had turned on his back. The dolphin wanted Sagan to scratch his stomach again, as the astronomer had done twice before. Elvar looked up at Sagan, waiting. Then, after a minute or so. the dolphin leapt up through the water and made a sound just like the word "more". The astonished astronomer went to the director of the institute and told him about the incident. "Oh, yes. That"s one of the words he knows," the director said, showing no surprise at all. Dolphins have bigger brain in proportion to their body size than humans have, and it has been known for a long time that they can make a number of sounds. What is more, these sounds seem to have different functions, such as warning each other of danger. Sound travels much faster and much further in water than it does in air. That is why the parts of the brain that deal with sound are much better developed in dolphin than in humans. But can it be said that dolphins have a "language", in the real sense of the word? Scientists don"t agree on this. A language is not just a collection of sounds, or even words. A language has a structure and what we call a grammar. The structure and grammar of a language help to give it meaning. For example, the two questions "Who loves Mary?" and "Who does Mary love?" mean very different things. If you stop to think about it, you will see that this difference doesn"t come from the words in the question but from the difference in structure. That is why the question "Can dolphins speak?" can"t be answered until we find out if dolphins not only make sounds but also arrange them in a grammatical order which affects their meaning.

单选题This college welcomes students from all over the world.A. receivesB. acceptsC. holdsD. chooses

单选题{{B}}第三篇{{/B}} {{B}} Attitudes to AIDS Now{{/B}} 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 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, 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 Gallup 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.

单选题{{B}}第一篇{{/B}} Countless people are born with(生来就具有某种特点)the susceptibility to inherit a genetic disease. But scientific progress, especially the art of interfering with(干涉,阻碍) the genetic makeup of the human body, has helped doctors prevent more and more inherited disorders in the last decade. Dr. Thomas Caskey of the Baylor University College of medicine in Houston, Texas, is a pioneer in molecular biology(分子生物学). Through the techniques of genetic engineering(基因工程), he transfers genes from one organism to another. Caskey uses a certain type of virus, called a retrovirus(逆转录病毒), as the vehicle for the gene transfer. He first cripples the virus by removing the portion it needs to reproduce itself. The crippled virus becomes harmless while still being able to deliver a cargo to its destination. The cargo in Caskey's experiment is the human A-D-A gene, taken from bone marrow. A-D-A stands for(代表) adenosine deaminase(腺苷脱氨酶), an important component of the human immune system. A defect in the A-D-A gene leads to immune deficiency, rendering(致使) the body defenseless against infections. Caskey's purpose was to see if the human A-D-A gene could repair the defective immune system of a mouse. In the experiment the mouse was given a dose of radiation heavy enough to destroy its immune system. The animal next was injected with the crippled virus carrying the human A-D-A gene. According to Caskey, "the mouse will die within 10 to 14 days unless a successful transfer of bone marrow cells takes place. So we lethally irradiate and subsequently rescue the mouse by bone marrow transplantation(骨髓移植)with the cells that have been infected with the virus." The mouse now carries the human gene that salvaged its immune system. Bone marrow transplantation has an established place in contemporary medical practice. Employed to restore the immune system of certain cancer patients and of people who have been exposed to radiation, bone marrow transplantation works only if there is a good match between donor and recipient. The procedure would be much easier if bone marrow were like blood. People with type O blood are universal donors(万能供体). Their blood may be transfused to those who have different blood types. Unfortunately, there is no such thing as a universal bone-marrow type. Researchers may have found a way, however, to overcome this problem. The solution, if it works, would be to implant the patient with his own, perfectly matching(型配), bone marrow. The idea, as Caskey explains it, is to "correct the patient's disease with his own ceils, but those cells have added to them a normally functioning gene. "In other words, surgeons would take defective bone-marrow cells from the patient and put them into a laboratory dish where the cells would be exposed to a crippled virus carrying a healthy AD-A gene from a donor. The A-D-A gene would repair the defective cells and then the cells would be reinjected into the patient. Thus, in Caskey words, "the patient would be transplanted by his own ceils containing the added normal gene." The technique sounds deceptively(靠不住地) simple. In reality, though(可是,不过, 然而), it is complex. A number of laboratories have tested various intermediate steps of the process, but, according to Caskey, "no single laboratory has put together the entire technology successfully, and highly reproducibly, to proceed with a gene transfer at-tempt in man." For some time now, the U.S. National Institute of Health has been taking a close look at(仔细,研究) the effectiveness and safety of the procedure, as well as the ethical questions it raises. There doesn't seem to be much concern about the ethics of gene transfer into a human being to correct a genetic defect. Dr. W. French Anderson of N. I. H. wrote recently that "claims that new organs, designed personalities, master races, or Frankenstein(佛兰肯思泰因，一个创造怪物而自己被它毁灭的医学研究者，英国女作家Mary W.Shelly同名小说中的主角) monsters will be created can be given no credence in the light of(根据,从……来看) what is presently known. "And he added that a well-informed public is the best assurance against any future misuses of genetic engineering.

单选题 Bill Gates: Unleashing Your Creativity I've always been an optimists and I suppose that is rooted in my belief that the power of creativity and intelligence can make the world a better place. For as long as I can remember, I've loved learning new things and solving problems. So when I sat down at a computer for the first time in seventh grade, I was hooked. It was a chunky old teletype machine and it could barely do anything compared to the computers we have today. But it changed my life. When my friend Paul Allen and I started Microsoft 30 years ago, we had a vision of "a computer on every desk and in every home," which probably sounded a little too optimistic at a time when most computers were the size of refrigerators. But we believed that personal computers would change their world. And they have. And after 30 years, I'm still as inspired by computers as I was back in seventh grade. I believe that computers are the most incredible tool we can use to feed our curiosity and inventiveness—to help us solve problems that even the smartest people couldn't solve on their own. Computers have transformed how we learn, giving kids everywhere a window into all of the world's knowledge. They're helping us build communities around the things we care about and to stay close to the people who are important to us, no matter where they are. Like my friend Warren Buffett, I feel particularly lucky to do something every day that I love to do. He calls it "tap-dancing to work". My job at Microsoft is as challenging as ever, but what makes me "tap-dancing to work" is when we show people something new, like a computer that can recognize your handwriting or your speech, or one that can store a lifetime's worth of photos, and they say, "I didn't know you could do that with a PC!" But for all the cool things that a person can do with a PC, there are lots of other ways we can put our creativity and intelligence to work to improve our world. There are still far too many people in the world whose most basic needs go unmet. Every year, for example, millions of people die from diseases that are easy to prevent or treat in the developed world. I believe that my own good fortune brings with it a responsibility to give back to the world. My wife, Melinda, and I have committed to improving health and education in a way that can help as many people as possible. As a father, I believe that the death of a child in Africa is no less poignant or tragic than the death of a child anywhere else, and that it doesn't take much to make an immense difference in these children's lives. I'm still very much an optimist, and I believe that progress on even the world's toughest problems is possible—and it's happening every day. We're seeing new drugs for deadly diseases, new diagnostic tools, and new attention paid to the health problems in the developing world. I'm excited by the possibilities I see for medicine, for education and, of course, for technology. And I believe that through our natural inventiveness, creativity and willingness to solve tough problems, we're going to make some amazing in all these areas in my life.

单选题The secretary is {{U}}expected{{/U}} to explore ideas for post-war reconstruction of the area.

单选题Practically all species of animals communicate either through sounds or through a large repertory of soundless codes. A. Simultaneously B. Almost C. Absolutely D. Basically

单选题She read a poem which depicts the splendor of the sunset.

单选题Cement was {{U}}seldom{{/U}} used in building during the Middle Ages.

单选题They are worried about their Ucapacity/U to invest in the future.

单选题The discovery was sensational. A. sexy B. surprising C. exceptional D. exciting

单选题This is especially true in today's extremely harsh economic climate.A. difficultB. easyC. normalD. intelligent

单选题The commercial telephone service was no longer {{U}}operative{{/U}}. A. creative B. moving C. rotating D. working

单选题Sleep Lets Brain File Memories To sleep. Perchance to file? Findings published online this week by the Proceedings of the National Academy of Sciences further support the theory that the brain organizes and stows memories formed during the day while the rest of the body is catching zzz"s. Gyorgy Buzsaki of Rutgers University and his colleagues analyzed the brain waves of sleeping rats and mice. Specifically, they examined the electrical activity emanating from the somatosensory neocortex (an area that processes sensory information) and the hippocampus, which is a center for learning and memory. The scientists found that oscillations in brain waves from the two regions appear to be intertwined. So-called sleep spindles (bursts of activity from the neocortex) were followed tens of milliseconds later by beats in the hippocampus known as ripples. The team posits that this interplay between the two brain regions is a key step in memory consolidation. A second study, also published online this week by the Proceedings of the National Academy of Sciences, links age-associated memory decline to high glucose levels. Previous research had shown that individuals with diabetes suffer from increased memory problems. In the new work, Antonio Convit of New York University School of Medicine and his collaborators studied 30 people whose average age was 69 to investigate whether sugar levels, which tend to increase with age, affect memory in healthy people as well. The scientists administered recall tests, brain scans and glucose tolerance tests, which measure how quickly sugar is absorbed from the blood by the body"s tissues. Subjects with the poorest memory recollection, the team discovered, also displayed the poorest glucose tolerance. In addition, their brain scans showed more hippocampus shrinkage than those of subjects better able to absorb blood sugar. "Our study suggests that this impairment may contribute to the memory deficits that occur as people age." Convit says. "And it raises the intriguing possibility that improving glucose tolerance could reverse some age-associated problems in cognition." Exercise and weight control can help keep glucose levels in check, so there may be one more reason to go to the gym.

单选题You have to be patient if you want to sustain your position.

单选题 阅读下面的短文，文中有15处空白，每处空白给出4个选项，请根据短文的内容从4个选项中选择1个最佳答案。 There is no doubt that we are living in a period of enormous population growth. In the past, it{{U}} (51) {{/U}}thousands of years for the world's population to double in size.{{U}} (52) {{/U}}today there are more people having families and fewer deaths from diseases. As(a){{U}} (53) {{/U}}, the population doubles in only 35 years. A(n){{U}} (54) {{/U}}supply of food is only one of the human needs that must be{{U}} (55) {{/U}}. Overcrowding has a highly undesirable effect on life. For example, if every available piece of land were used for producing food, it would be very difficult to{{U}} (56) {{/U}}proper housing for people, as would health care and recreation.{{U}} (57) {{/U}}these reasons, more governments are helping families to understand the problems of{{U}} (58) {{/U}}population. They give 'family planning' advice to families that request it. Such families can plan to have the number of children they want, at times when they are best able to care{{U}} (59) {{/U}}children and give them a good start in life.{{U}}(60) {{/U}}rice that have been highly successful in Asia and in{{U}} (61) {{/U}}African countries. The significance of such work was recognized by the awarding of the 1970 Nobel Peace Prize{{U}} (62) {{/U}}one of the plant breeders of the 'green revolution'.{{U}} (63) {{/U}}to grow well, the improved seeds need large{{U}} (64) {{/U}}of fertilizer and water, which are not always {{U}}(65) {{/U}}. Many fertilizers are made up of petroleum, and higher prices for oil have resulted in smaller supplies of fertilizers.

单选题She could not answer, it was an immense load off her heart.A. naturalB. fatalC. tinyD. enormous

单选题 阅读下面这篇短文，短文后列出了7个句子，请根据短文的内容对每个句子作出判断。如果该句提供的是正确信息，请选择A项；如果该句提供的错误信息，请选择B项：如果该句的信息文章中没有提及，请选择C项。 {{B}}Spare a Kidney?{{/B}} It is no longer unusual for a spouse or relative to donate a kidney to a loved one, but the number of Americans who have given a kidney to a friend, a co-worker or even a complete stranger has risen sharply from 68 in 1994 to 176 in 1998. There are many reasons. First, it's possible to live a normal life with only one kidney. (The remaining kidney enlarges to make up most of the difference.) In addition a kidney from a live donor lasts longer than a kidney taken from someone who has died suddenly. But the biggest change in the past few years is that transplant surgeons have started using laparoscopic techniques to remove the donor kidney through a much smaller incision, and this can cut recovery time for the donor from six weeks to four weeks. Just because you do something, however, it doesn't mean you should. Donating a kidney means undergoing an operation that carries some risk. You could argue that you may be helping to save a life, but you certainly can't pretend that you're better off with one kidney instead of two. So, what are the risks? "As with any major operation, there is a chance of dying, of reoperation due to bleeding, of infection, of vein clots in the legs or a hernia at the incision," says Dr. Arthur Matas, director of the renal-transplant program at the university of Minnesota Medical Center in Minneapolis. Even laparoscopy, a relatively new technique for kidney donation, is not risk-free. Doctors estimate that chances of dying from the procedure are about 3 in 10,000. There's no money to be made; selling an organ is illegal. But the recipient's insurance normally covers your operation and immediate aftercare. Your costs can include hotel bills, lost pay during recovery or possible future disability. Although transplant centers must evaluate any potential donor's suitability, it never hurts to have an independent opinion. The most common contraindications are heart disease, diabetes and high blood pressure. Never let anyone, not even a close relative, pressure you into giving up an organ--no matter if you're healthy. "There's often the feeling that you're not a good friend, father, mother if you don't do this," says Arthus Caplan, director of the University of Pennsylvania's center for Bioethics. Some transplant centers will invent a "medical problem" on behalf of those who are reluctant to donate but feel they can't say no.

单选题The room is dim and quiet.

单选题AIDS Eight to ten million people around the world are now infected with the virus that causes AIDS, and the incidence of the infection is rising dramatically in some parts of the world, the World Health Organization reports. The estimate is 1 with an earlier projection by the organization that 15 million to 20 million people would be infected by HIV by the year 2005. The 2 reflect the growing 3 of the AIDS virus around the world. "It is clear that the problem of HIV infection around the globe is 4 rapidly, especially in 5 countries in Africa and Asia," said Dr. Michael Merson, the director of the agency"s worldwide programs on AIDS. The new estimates are based on a recently 6 analysis of blood tests in which the AIDS virus was found in 1988 and 1989. The analysis showed that the 7 of HIV infection is slowing in industrialized countries. But in sub-Saharan African, cases of HIV infection have increased 8 about 5 million from 2.5 million in 1987. That year, most infected people were found in big cities; now the virus is spreading to 9 areas. The agency calculated that about one 10 40 adult men and women is infected in that region. 11 from Southern Asia, including Thailand and India, showed marked increase in HIV infection among female prostitutes (妓女) and people who inject drugs into themselves. The 12 number of HIV infection in Asia has risen from next to nothing two years ago to at least 500,000, the agency reported. The agency also 13 a rising incidence of HIV infection, AIDS cases and 14 among women and children in the 1990s, with three million of them 15 to die in the next decade.