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  3. "I have great confidence that by the end of the decade we’ll know in vast detail how cancer cells arise," says microbiologist Ro

"I have great confidence that by the end of the decade we’ll know in vast detail how cancer cells arise," says microbiologist Ro

admin2018-03-01  76
问题     "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 may 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 statistics are still discouraging—13 percent for lung cancer, and 2 percent for cancer of the pancreas.
    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, are inactive in normal cells. 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 suggests that we will never prevent all cancers. "Changes are a normal part of the evolutionary process," says oncologist 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."
What can we infer from the first paragraph?
选项 A、Robert Weinberg holds that cancer can be cured by the end of the decade.
B、It was fifty or sixty years before we know how to cure the cancer.
C、We have already understood how cancer cells arise.
D、We still have a long way to go to find cancer cures.
答案D
解析 选项D对应第一段最后一句，从这一句话可以看出，即使我们已经发现了某种病的病理原因，我们仍然要花五六十年的时间才能找到治疗方案。因此可以推测出，我们要找到治疗癌症的办法还有很长的路要走。选项A对应这一段的第一句，但是第一句只说到这个10年结束的时候，我们就搞清楚了癌细胞病变的很多细节，但是并没有提到癌症可以被治愈，而且这也和最后一句是冲突的，因此选项A错误。选项B是对本段最后一句曲解，最后一句话是Pasteur发现的一个现象：即使发现了很多感染的病因，要找到治疗方案仍然需要花费五六十年的时间，这里并不是说癌症在五六十年的时间中就能被治愈。选项C也与第一句冲突，故错误。
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