单选题NewAttemptstoEradicateAIDSVirusA.high-profileattempttoeradicatetheAIDSvirusinafewpatientscontinuestoshowpromise.Butresearcherswon'tknowforayearormorewhetheritwillwork,scientistDavidHotoldjournalistshereWednesdayfortheFourthConferenceinVirusesandInfections."Thisisastudythat'sinprogress,"saysHo,headoftheAaronDiamondAIDSResearchCenter.NewYork.Thestudyinvolves20peoplewhostartedcombinationsofanti-HIVdrugsveryearlyinthecourseofthedisease,within90daysoftheirinfections.They'vebeentreatedforupto18months.Fourothershavedroppedoutbecauseofsideeffectsorproblemscomplyingwiththeexactingdrugsystem.ThedrugshaveknockedtheAIDSvirusdowntoundetectablelevelsinthebloodofallremainingpatients.And,inthelatestdevelopment,scientistshavenowtestedlymphnodesandsemenfromafewpatientsandfoundnovirusreproducingthere,Hosays."Bearinmindthatundetectabledoesnotequalabsent,"Hosays.Hohascalculatedthatthedrugsshouldbeabletowipeoutremainingviruses—atleastfromknownreservoirsthroughoutthebody—intwotothreeyears.Buttheonlywaytoproveeradicationwouldbetostopthedrugsandseeiftheviruscomesback.OnWednesday,Hosaidhewouldn'taskanypatienttoconsiderthatstepbeforeyearsoftreatment.Andheemphasizedthatheisnoturgingwidespreadadoptionofsuchearly.aggressivetreatmentoutsideoftrials.Nooneknowsthelong-termrisks.Butotherscientistsarelookingatsimilarexperiments.Afederallyfundedstudywillput300patientsontriple-drugtreatmentsandthenseeifsomerespondingwellaftersixmonthscancontinuetosuppressthevirusonjustoneortwodrugs,saysresearcherDouglasRichmanoftheUniversityofCalifornia,SanDiego.Somepatientsinthatstudyalsomaybeofferedthechancetostoptherapyafter18monthsormore,hesays.

单选题 下面有3篇短文，每篇短文后有5道题，每道题后面有4个选项。请根据文章的内容，从每题所给的4个选项中选择1个最佳答案。{{B}}第一篇{{/B}} {{B}}Exercise Lowers Employers' Health Costs{{/B}} Companies can save millions in health-care costs simply by encouraging their employees to exercise a little bit, researchers reported on Friday. They said obese (肥胖的) employees had higher health-care costs, but lowered those expenses by exercising just a couple of times a week — without even losing any weight. Feifei Wang and colleagues at the University of Michigan studied 23,500 workers at General Motors. They estimated that getting the most sedentary (惯于久坐的) obese workers to exercise would have saved about $790,000 a year, or about 1.5I percent of health-care costs for the whole group. Company-wide, the potential savings could reach $7.1 million per year, they reported in the Journal of Occupational and Environmental Medicine. Of the whole group of workers, about 30 percent were of normal weight, 45 percent were overweight (超重的), and 25 percent were obese. Annual health-care costs averaged $2,200 for normal weight, $2,400 for the overweight, and $2,700 for obese employees. But among workers who did no exercise, health-care costs went up by at least $100 a year, and were $3,000 a year for obese employees who were sedentary. But adding two or more days of light exercise — at least 20 minutes of exercise or work hard enough to increase heart rate and breathing — lowered costs by on average $500 per employee a year, the researchers found. "This indicates that physical activity behavior could reduce at least some of the harmful effects of excess body fat, and in consequence, help lower the health-care costs," Wang and colleagues wrote.

单选题The police{{U}} contended{{/U}} that the difficulties they faced were too severe.

单选题Mary has derived a good deal of benefit from her job.

单选题The woman's {{U}}scowl{{/U}} showed she was not satisfied with the service here.

单选题Which of the following is NOT mentioned as a step to control smoking?

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。 Researchers have known for years that animals have a "clock" somewhere in their brains a control-centre that regulates circadian(生物节奏的) rhythms. Circadian rhythms are the body's daily biological cycles, controlling such activities as sleep and wakefulness. In November 1988, neuroscientists at the University of Virginia in Charlotteville reported that the supra chasmatic nucleus(SCN), a small cluster(束)of cells in the middle of the brain that neuroscientists have long suspected of playing a role in daily rhythms, is the long-sought biological clock. The investigators performed a series of tissue-transplant experiments with hamsters (仓鼠). Some of the animals were normal hamsters, which have a circadian cycle of 24 hours; the others were mutant(变异型)hamsters whose cycles were only 20 or 22 hours long. The scientists first removed the SCN from the brans of the hamsters in both groups. They then implanted an SCN from a mutant hamster into the brain of each normal animal, and vice versa. When the hamsters had recovered from their operations, the circadian rhythms of the two groups were reversed. The normal hamsters had a daily cycle of 20 to 22 hours, and the mutants were on a 24-hour cycle. The identification of the internal clock is an important stepping-stone in understanding the basic, automatic mechanisms of brain function. It may also help in finding ways to relieve human sleep disorders.

单选题The planned general strike represents a vital economic challenge to the government. A. an important B. a specific C. a quick D. a trivial

单选题We {{U}}explored{{/U}} the possibility of closer trade links at the conference.

单选题Louis was asked to {{U}}name{{/U}} the man who stole her purse.

单选题It can be inferred from the last paragraph that

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.