last-1-1-16

worri

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.

(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.

答案是C。为什么呢？请指点。

cranberry

文中的最后一句已经暗示了实际上是这个措施导致了故障报告的增多而不是实际上就发生了这么多故障。