prep

real700

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?

• APartorian trucking companies have so far used triple-trailer trucks on lightly traveled sections of major highways only.  分析A选项
• BNo matter what changes Partoria makes in the regulation of trucking, it will have to keep some smaller roads off-limits to all large trucks.  分析B选项
• CVery few fatal collisions involving trucks in Partoria are collisions between two trucks.  分析C选项
• DIn Partoria, the safety record of the trucking industry as a whole has improved slightly over the past ten years.  分析D选项
• EIn 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.  
  求问c选项为什么不对啊！ 如果不是因为两个卡车相撞，那么就是别的因素，那换了卡车也没有用啊。。。求教！！！
  

newyork201999

结论：一种可以降低高速路死亡的方式是要求运输者们使用triple-trailer 卡车

问削弱

最直接的削弱就如A所提及的triple-trailer 压根不是更安全的缘由，triple-trailer 只所以涉及严重事故少是因为一般只在交通量很低的路段使用而已

运输公司只用triple-trailer 跑车流量很小的路段，跑长途大流量的都是其他卡车。当把卡车都换成triple-trailer ，那triple-trailer 也得跑大流量的路线。

C . 很少的致命车祸是在两辆卡车之间
这有什么关系呢？ 这只是说明致命车祸主要是卡车和小车之间发生，并不能削弱结论。如果triple-trailer 真降低事故，把卡车都换成triple-trailer ，那卡车（triple-trailer）和小车的事故就应该降低

real700

恩恩 谢谢这位好心人！