28-17: In the nation of Partoria, large trucks currently account for 6 percent of miles driven on Partoria’s roads but are involved in 12 percent of all highway fatalities. The very largest trucks – those with three trailers – had less than a third of the accident rate of single- and double-trailer trucks. Clearly, therefore, one way for Partoria to reduce highway deaths would be to require shippers to increase their use of triple-trailer trucks. Which of the following, if true, most seriously weakens the argument? A: Partorian trucking companies have so far used triple-trailer trucks on lightly traveled sections of major highways only. B: No matter what changes Partoria makes in the regulation of trucking, it will have to keep some smaller roads off-limits to all large trucks. C: Very few fatal collisions involving trucks in Partoria are collisions between two trucks. D: In Partoria, the safety record of the trucking industry as a whole has improved slightly over the past ten years. E: In Partoria, the maximum legal payload of a triple-trailer truck is less than three times the maximum legal payload of the largest of the single-trailer trucks 很多xdjm给出答案为A,但我觉得A是无关选项，A只说了P的trucking companies用3节truck太多了，但并不能说明p的增加3节truck的策略去减低事故是错的。我觉得选不出什么答案，所以选了B.请大家给出自己的答案和理由！！
这是削弱题,require shippers to increase their use of triple-trailer trucks 能够reduce highway deaths 一般说来可以找出这种措施的漏洞.但答案中没有. 那么我们就应该看得出此结论的前提, very largest trucks – those with three trailers – had less than a third of the accident rate of single- and double-trailer trucks. 所以我们可以削弱前提,即这些车处的环境不一样,即没有可比性.所以A是对的
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发表于 2005-11-29 13:44:00
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