单选题During the construction of skyscrapers, cranes are used to______ building materials to the upper floors.(2011年四川大学考博试题)

单选题The recordings differ from written stories in that ______.

单选题Biologists have made a lot of progress in understanding ageing. They have not, however, been able to do much about slowing it down. A piece of work reported in this week's Nature by Darren Baker, though, describes an extraordinary result that points to a way the process might be improved. Dr Baker has shown— in mice, at least—that ageing body cells not only suffer themselves, but also have adverse effects on otherwise healthy cells around them. If such ageing cells are selectively destroyed, these adverse effects go away. The story starts with an observation that senescent cells often produce a molecule called P16INK4A. Dr Baker genetically engineered a group of mice that were already quite unusual. They had a condition called progeria, meaning that they aged much more rapidly than normal mice. The extra tweak he added to the DNA of these mice was a way of killing cells that produce P16INK4A. He did this by inserting into the animals' DNA, near the gene for P 16INK4A, a second gene that was, because of this proximity, controlled by the same genetic switch. This second gene, activated whenever the gene for P16INK4A was active, produced a protein that was harmless in itself, but which could kill the senescent cells by the presence of a particular drug. The results were spectacular. Mice given the drug every three days from birth suffered far less age-related body-wasting than those which were not. Their muscles remained plump and effective. And they did not suffer cataracts of the eye. They did, though, continue to experience age-related problems in tissues that do not produce P16INK4A as they get old. In particular, their hearts and blood vessels aged normally. For that reason, since heart failure is the main cause of death in such mice, their lifespans were not extended. Regardless of the biochemical details, the most intriguing thing Dr Baker's result provides is a new way of thinking about how to slow the process of ageing—and one that works with the grain of nature, rather than against it. Actually eliminating senescent cells may be a logical extension of the process of shutting them down, and thus may not have adverse consequences. It is not an elixir of life, for eventually the body will run out of cells, as more and more of them reach their Hayflick limits. But it could be a way of providing a healthier and more robust old age than people currently enjoy. Genetically engineering people in the way that Dr Baker engineered his mice is obviously out of the question for the foreseeable fixture. But if some other means of clearing cells rich in P 16INK4A from the body could be found, it might have the desired effect. The wasting and weakening of the tissues that accompanies senescence would be a thing of the past, and old age could then truly become ripe.

单选题Language, culture, and personality may be considered ______ of each other in thought, but they are inseparable in fact.(2010年厦门大学考博试题)

单选题Man: I have to phone my secretary before we leave. Woman: There is not much time. Maybe you"d better get Tom to phone for you. Question: What does the woman mean?

单选题Woman: Professor Smith, I really need the credits to graduate this summer.Man: Here in this school: the credits are earned, not given.Question: What do we learn from the conversation?

单选题The human nose is an underrated tool. Humans are often thought to be insensitive smellers compared with animals, but this is largely because,【C1】______animals, we stand upright. This means that our noses are【C2】______to perceiving those smells which float through the air, missing the majority of smells which stick to surfaces. In fact, though, we are extremely sensitive to smells, even if we do not generally realize it. Our noses are capable of【C3】______human smells even when these are【C4】______to far below one part in one million. Strangely, some people find that they can smell one type of flower but not another, whereas others are sensitive to the smells of both flowers. This may be because some people do not have the genes necessary to generate【C5】______smell receptors in the nose. These receptors are the cells which sense smells and send【C6】______to the brain. However, it has been found that even people insensitive to a certain smell at first can suddenly become sensitive to it when【C7】______to it often enough. The explanation for insensitivity to smell seems to be that brain finds it inefficient to keep all smell receptors working all the time but can【C8】______new receptors if necessary. This may also explain why we are not usually sensitive to our own smells we simply do not need to be. We are not【C9】______of the usual smell of our own house but we notice new smells when we visit someone else's. The brain finds it best to keep smell receptors【C10】______for unfamiliar and emergency signals such as the smell of smoke, which might indicate the danger of fire.

单选题One of the first known methods of advertising is the outdoor ______ . A．display B．Journey C．exercise D．adventure

单选题Which of the following is the organization of the passage?

单选题When you are in your room, leave the door ______ so that your visitors do not have to knock. A. open B. opened C. opening D. being open

单选题It seems to me that you have been______your studies recently.

单选题The role of American women______significantly from the time the nation was born, to the modern era of the 1950s and 1960s.

单选题 {{B}}Directions: {{/B}} There are ten short incomplete dialogues between two speakers, each followed by four choices marked A, B, C and D. Choose the answer that appropriately suits the conversational context and best completes the dialogue. Mark your answer on the {{B}}ANSWER SHEET{{/B}} by drawing with a pencil a short bar across the corresponding letter in the brackets.

单选题The book gives a brief______off the course of his research up till now.

单选题The main impact the Telecommunications Act of 1996 had on radio was to______.

单选题Modern linguistics began from the Swiss linguist______, who is often described as " father of modern linguistics".

单选题The construction of the building ______ by the end of this month. A. will have completed B. will have been completed C. will be completed D. will completed

单选题When my son started going to "school" full time in February, I readied myself for immunological battle. Day-care kids get sicker than children who stay at home, and I knew mine" would, too. But other parents assured me that by kindergarten he"d be the healthiest kid in class. Last week parenting message boards lit up when a University of California, Berkeley, researcher presented unpublished data showing that children who attend playgroups or day care have a 30 percent lower risk of developing childhood leukemia than kids who don"t, possibly because they are exposed to more infections early in life. The human immune system is an elegant mix of two parts—a built-in, or innate, system and an acquired one. The innate system has already read the manual on generic germs. The acquired system, by contrast, is a bookworm, reading on the go,, learning with every new microbial visitor and growing wiser as it ages. Together, the two systems assess the foods we eat, the particles we breathe, the bacteria we touch, then determine whether or not to attack. Can a young immune system handle so much new information? Research published over the past decade is reassuring. Scientists at the University of Arizona found that 2-year-olds who attend day care in the first six months of life have almost twice as many colds as stay-at-home kids. But they have a third fewer colds between the ages of 6 and 11. By 13, there"s no difference in the groups, suggesting that the kids" immune systems catch up with each other. Several studies have found that children who go to day care early in life are also less likely to develop asthma. The Arizona scientists discovered that high-risk children who start day care before 3 months old have lower levels of immunoglobutin E—a marker of allergic susceptibility connected to asthma-than non-day-care kids. Those levels remain low for the first three years of life. Anne Wright, the study"s lead author, says this doesn"t necessarily mean that kids benefit from being sick more often. She believes the findings support the "hygiene hypothesis," which suggests that simply being exposed to more microbes—which run rampant at day care—educates the immune system, making it less likely to launch unwarranted warfare. All this is good to know. But I had to ask the experts: why am I getting: so sick? "Because you live with the source," says Liu. And I hug and kiss him a lot, too, so I"m probably getting a big dose of germs. It"s also possible that my immune system"s memory has faded a bit, making old harmless viruses look new and dangerous. Or I may be meeting bugs my immune system has never seen before. The most comforting words I heard were from Columbia University pediatrician Philip L. Graham Ⅲ, who told me that pediatricians get horribly sick during their first year of treating patients. After that, they"re immunological powerhouses.

单选题Though not the ideal shape for a Christmas stocking, this slim little volume could nevertheless make a welcome seasonal gift. Launched in Britain at the end of October, and covering just under 100 pages, it is not much more than an extended essay. But it presents an interesting idea eloquently and clearly, offering digestible brain food in the middle of excessive turkey and television. The author of Hierarchy Is Not the Only Way, Gerard Fairtlough, was a senior executive with Shell for many years before he left in 1980 to found a new biotechnology company called Celltech—recently bought by UCB, a Belgian group, for over $2 billion. He knows how businesses are run—both well-established organisations, such as Shell, in which it can be hard to see an alternative to the "way things are done around here", and new firms, where the founders" enthusiasm can evaporate if it has to be organized into an organogram. The author"s thesis is that we are all addicted to hierarchy—partly because that is how we are hardwired, as are our simian cousins, but also because we do not realise there are other ways to run organisations. "The powerful status of hierarchy," writes Mr. Fairtlough, "makes us think the only alternative is disorganisation...we only compare hierarchy with anarchy or chaos." There are, he says, two alternatives to hierarchy. One is heterarchy; the other, "responsible autonomy." Heterarchy is the form of structure commonly found in professional-service firms, the partnerships of accountants or lawyers in which key decisions are taken by all the partners jointly. With responsible autonomy "an individual or a group has autonomy to decide what to do, but is accountable for the outcome of the decision." "Accountability," says Mr. Fairtlough, "is what makes responsible autonomy different from anarchy." The author says that hierarchy is so deeply rooted that it will take years before there is any significant change. But he perhaps gives too little credit to the many companies that have moved along the spectrum from hierarchy to responsible autonomy. BP, for example, a huge multinational, has managed to split authority into much smaller units in recent years and has reduced the staff in its headquarters. Toyota, likewise, evolved towards greater autonomy as it discovered that the only effective way to carry out its famous "just-in-time" system of stock control was by delegating responsibility for ordering stock to the person closest to the coal face. The fact that these are among the most successful companies in the world today strengthens Mr. Fairtlough"s case.