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20. A rise in the percentage of all 18-year-olds who were recruited by the armed services of a small republic between 1980 and 1986 correlates with a rise in the percentage of young people who dropped out of high school in that republic. Since 18-year-olds in the republic are generally either high school graduates or high school dropouts, the correlation leads to the conclusion that the republic’s recruitment rates for 18-year-olds depend substantially on recruitment rates for high school dropouts. Which one of the following statements, if true, most weakens the argument? (A) A large number of 18-year-old high school graduates were recruited for the republic’s armed services in 1986 than in 1980. (B) Many of the high-technology systems used by the republic’s armed services can be operated only by individuals who have completed a high school education. (C) Between 1980 and 1986 the percentage of high school graduates among 18-year-olds recruited in the republic rose sharply. (D) Personnel of the republic’s armed services are strongly encouraged to finish their high school education. (E) The proportion of recruits who had completed at least two years of college education was greater in 1986 than in 1980. 答案C，为什么？还有B为什么不对啊？按B的说法，不是说明 republic雇佣的是high school graduates ，而不是dropouts啊。 21. Historian: We can learn about the medical history of individuals through chemical analysis of their hair. It is likely, for example, that Isaac Newton’s psychological problems were due to mercury poisoning; traces of mercury were found in his hair. Analysis is now being done on a lock of Beethoven’s hair. Although no convincing argument has shown that Beethoven ever had a venereal disease, some people hypothesize that venereal disease caused his deafness. Since mercury was commonly ingested in Beethoven’s time to treat venereal disease, if researchers find a trace of mercury in his hair, we can conclude that this hypothesis is correct. Which one of the following is an assumption on which the historian’s argument depends? (A) None of the mercury introduced into the body can be eliminated. (B) Some people in Beethoven’s time did not ingest mercury. (C) Mercury is an effective treatment for venereal disease. (D) Mercury poisoning can cause deafness in people with venereal disease. (E) Beethoven suffered from psychological problems of the same severity as Newton’s. 答案B，不懂。A为什么不对？ Conservationist: The population of a certain wildflower is so small that the species is headed for extinction. However, this wildflower can cross-pollinate with a closely related domesticated daisy, producing viable seeds. Such cross-pollination could result in a significant population of wildflower-daisy hybrids. The daisy should therefore be introduced into the wildflower’s range, since although the hybrid would differ markedly from the wildflower, hybridization is the only means of preventing total loss of the wildflower in its range. 34. Which one of the following is an assumption on which the conservationist’s reasoning depends? (A) The wildflower currently reproduces only by forming seeds. (B) The domesticated daisy was bred from wild plants that once grew in the wildflower’s range. (C) Increasing the population of the wildflower will also expand its range. (D) Wildflower-daisy hybrids will be able to reproduce. (E) The domesticated daisy will cross-pollinate with any daisy like plant. 答案D，我知道D是对的。A怎么不对啊？对A取非的话，不是说wildflower还可以通过其他方法reproduces吗，那么hybridization is the only means of preventing total loss of the wildflower in its range.不就错了吗
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发表于 2009-8-9 21:51:00
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