以下是引用dcatcher在2006-10-16 7:51:00的发言: 我也觉得答案是B. 题目讲其他species population增加,但并不是说相对白脚鼠的比例增加,如果白脚鼠和其他种类以相同的比例增加的话,dear tick吃到白脚鼠的机率是一样的,在这种情况下,带菌的tick的数目不会减少,人类感染这种病的数目并不会减少. 所以C不是正确的选项.
一开始选b,后来觉得还是c对,b是无关选项。我觉得这题导致争论的原因是argument的问题,到底什么是argument,仔细多读几遍可以发现题目的argument不是the number of people contracting Lyme disease would likely decline.而是 if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline,也就是说题目要讨论的是other species were increased会不会导致t的减少从而导致people的减少,而不是说最后people感染的人减少,这是两个概念,只要other species were increased能促进感染人数的减少就可以了,无论最后结果如何,即便是最后感染的人数增加了(通过其他方式),也不影响other species were increased能对感染人数的减少起促进作用这一结论的有效性。 不知道说明百了没有 if the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline,也就是说题目要讨论的是other species were increased会不会导致t的减少从而导致people的减少,而不是说最后people感染的人减少,这是两个概念,只要other species were increased能促进感染人数的减少就可以了,无论最后结果如何,即便是最后感染的人数增加了(通过其他方式),也不影响other species were increased能对感染人数的减少起促进作用这一结论的有效性。 不知道说明百了没有
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