单选题If a child is left alone, he'll lose his {{U}}zest{{/U}} for life and his desire to find out new things for himself.

单选题{{B}}第二篇{{/B}} "I have great confidence that by the end of the decade we'll know in vast detail how cancer cells arise," says microbiologist Robert Weinberg, an expert on cancer, "But," he cautions, "some people have the idea that once one understands the causes, the cure will rapidly follow. Consider Pasteur. He discovered the causes of many kinds of infections, but it was fifty or sixty years before cures were available." This year, 50 percent of the 910 000 people who suffer from cancer will survive at least five years. In the year 2000, the National Cancer Institute estimates, that figure will be 75 percent. For some skin cancers, the five-year survival rate is as high as 90 percent. But other survival statistic(统计)rate still discouraging-13 percent for lung cancer, and 2 percent for cancer of the pancreas(胰腺). With as many as 120 varieties in existence, discovering how cancer works is not easy. The researchers made great progress in the early 1970s, when they discovered that oncogenes, which are cancer-causing genes(基因), are inactive in normal ceils. Anything from cosmic rays to radiation to diet may activate a dormant oncogene, but how remains unknown. If several oncogenes are driven into action, the cell, unable to turn them off, becomes cancerous. The exact mechanisms involved are still mysterious, but the likelihood that many cancers are initiated at the level of genes suggest that we will never prevent all cancers. "Changes are a normal part of the evolutionary process," says oneologist William Hayward. Environmental factors can never be totally eliminated; as Hayward points out, "We can't prepare a medicine against cosmic rays." The prospects for cure, though still distant, are brighter. "First, we need to understand how the normal cell controls itself. Second, we have to determine whether there are a limited number of genes in cells, which are always responsible for at least part of the trouble. If we can understand how cancer works, we can counteract its action."

单选题The policemen acted quickly because lives were at stake.

单选题Smoking is Uinhibited/U in public places.

单选题The government has put forward new proposals to tackle the problem of increasing crime.A. brought upB. brought inC. brought backD. brought forward

单选题This new policy has led to a dramatic increase in production. A. minor B. striking C. fixed D. modest

单选题An old friend called on me the day before yesterday.

单选题Ulcers Even though ulcers appear to run in families, lifestyle plays more of role than genetic factors in causing the illness, according to a report in the April 13th Journal of Internal Medicine. In particular, smoking and stress in men and the regular use of pain releasing medicines in women were linked with an increased risk of developing an ulcer. Overall, 61% of ulcer risk appears to be due to environmental actors, such as smoking, and the remaining 39% is due to genes according to Dr. Ismo Raiha of the University of Turky and colleagues at the University of Helsinki, Finland. Some researchers had suggested that families may spread Helicobacteria pylori, the bacteria that can cause ulcers. However, the new study suggests this is unlikely, according to the report. Raiha and colleagues studied data from more than 13,000 pairs of twins "to examine the roles of genetic and environmental factors in the origin of peptic ulcer disease," they explain. Both twins were more likely to develop an ulcer if the pair were genetically the. same as compared with a pair of fraternal twins, suggesting that there must be some genetic susceptibility to ulcer development. However, the risk was no greater in twins living together compared with twins living apart, suggesting that shared exposure to H. pylori was not to blame. "Environmental effects were not due to factors shared by family members, and they were related to smoking and stress in men and the use of analgesics in women," the authors wrote. "The minor effects of shared environment to disease liability do not support the concept that the grouping of risk factors, such as H. pylori infection, would explain the genetic factor of peptic ulcer disease," they concluded.

单选题Norman Blamey is an artist of deep {{U}}convictions{{/U}}. A. statements B. beliefs C. suggestions D. claims

单选题Breakfast Studies show that children who eat breakfast do better in school. It doesn't take much further thought to believe that adults will feel better and perform better at work as well. Whether you work at home, on the farm, at the office, at school, or on the road, it is not a good idea to skip (故意略去) breakfast. If we don't eat breakfast, we are likely to become tired when our brains and bodies run Iow on fuel. By mid-morning, a lot of us grab a cup of coffee, or wolf down a sugary candy bar to wake up again. This might work for a few minutes, but by lunchtime we are hungry, bad-tempered, and perhaps our mood might make us a little more likely to make unhealthy choices at lunch. Eating a good breakfast sets the tone for the rest of the day. People who eat breakfast are generally more likely to maintain a healthy weight. Many people believe that they will lose weight if they skip meals, but that isn't a good idea. The body expects to be refueled a few times a day, so start with a healthy breakfast. A healthy breakfast should contain some protein (蛋白质) and some fiber (纤维). Protein can come from meat, eggs, beans, or soy (大豆). Fiber can be found in whole cereals (谷物), grains or in fruits. A good example of a healthy breakfast might be something simple like a hard boiled egg, an orange, and a bowl of whole grain cereal with soy milk.

单选题If you have any Ucomplaint/U please see the manager.

单选题Poor children should not be deprived of the opportunity to participate in sports whenever possible.A. deniedB. retreatedC. oppressedD. refused

单选题You have to be patient if you want to {{U}}sustain{{/U}} your position. A. maintain B. better C. acquire D. support

单选题Efforts to preserve the peace have failed.

单选题I notified him that my address had changed.

单选题In the United States educational system, intermediate school is the transitional phase between the primary grades and high school.A. stageB. notionC. patternD. alternative

单选题The ice is not thick enough to bear the weigh of a tank.

单选题Don't try to dignify those few hairs on your face by calling them a beard.

单选题下面有3篇短文，每篇短文后有5道题。请根据短文回答其后面的问题，为每题确定一个最佳答案。 {{B}}第一篇{{/B}} Enjoy Sun Shine People travel for a lot of reasons. Some tourists go to see battlefields or religious shrines. Others are looking for culture, or simply want to have their picture taken in front of famous places. But most European tourists are looking for a sunny beach to lie on. Northern European are willing to pay a lot of money and put up with a lot of inconveniences for the sun because they have so little of it. Residents of cities like London, Copenhagen, and Amsterdam spend a lot of their winter in the dark because the days are so short, and much of the rest the year in the rain. This is the reason the Mediterranean has always attracted them, Every summer, more than 25 million people travel to Mediterranean resort and beaches for their vacation. They all come for the same reason: sun！ The huge crowds mean lots of money for the economies of Mediterranean countries. Italy's 30,000 hotels are hooked solid every summer. And 13 million people camp out on French beaches, parks and roadsides. Spain's long sandy coastline attracts more people than anywhere else. 37 million tourists visit yearly, or one tourist for every person living in Spain. But there are signs that the area is getting more tourism than it can handle. The Mediterranean is already one the most polluted seas on earth. And with increased tourism, it's getting worse. The French can't figure out what to do with all the garbage left by campers around St. Tropez. And in many places, swimming is dangerous because of pollution. None of this, however, is spoiling anyone's fun. The Mediterranean gets more popular every year with tourists. Obviously, they don't go there for clean water and solitude. They tolerate traffic jams and seem to like crowded beaches. They don't even mind the pollution. No matter how dirty the water is, the coastline still looks beautiful. And as long as the sun shines, it's still better than sitting in the cold rain in Berlin, London, or Oslo.

单选题America's emphasis on the importance of education for everyone has Uspurred/U scientific research,