ff宝典61，周四就考试了，麻烦大家啦

61. Investigators concluded that human failure was not responsible for the fatal airplane crash last August, and since that time new and more stringent rules for identifying and reporting mechanical problems have been in effect. That accounts for the fact that reports of airplane mechanical problems have increased in frequency by 50 percent since last August.

Which one of the following is an assumption underlying the argument in the passage?

(A) Airplane travel is still relatively safe, despite the increase in reported mechanical problems.

(B) Mechanical problems in airplanes have increased dramatically since last August.

(C) Mechanical problems in airplanes have not increased by 50 percent since last August. ---正解

(D) Airlines are less reluctant to report mechanical problems than they previously were.
   

(E) Mechanical problems in airplanes have become easier to detect since last August

这个C项...跟题中的那个句除了加了个not有啥区别吗？加了个not也不能是假设吧...

一点想法供参考哈，不对之处请牛人纠正：

这道题的结论：新的严格的报告制度导致了关于机械故障的报告增加了50%。C是排除他因的假设，也即故障本身没增加只是制度严格了，以前可能不用汇报的故障现在也报上去了，导致报告量上升。

我们也可对C项取非来判定，如果对C取非：飞机的机械故障增加了50%，那么就是由于本身故障增加了，所以故障报告多了，这和题目结论（由于严格的报告制度导致机械故障报告多）相冲突，选C。