LSAT-2-2-19

19.   How do the airlines expect to prevent commercial plane crashes? Studies have shown that pilot error contributes to two-thirds of all such crashes. To address this problem, the airlines have upgraded their training programs by increasing the hours of classroom instruction and emphasizing communication skills in the cockpit. But it is unrealistic to expect such measures to compensate for pilots’ lack of actual flying time. Therefore, the airlines should rethink their training approach to reducing commercial crashes.

Which one of the following is an assumption upon which the argument depends?

(A) Training programs can eliminate pilot errors.

(B) Commercial pilots routinely undergo additional training throughout their careers.

(C) The number of airline crashes will decrease if pilot training programs focus on increasing actual flying time.

(D) Lack of actual flying time is an important contributor to pilot error in commercial plane crashes.

(E) Communication skills are not important to pilot training programs.

答案是D，请教C为什么不对
我的想法是：
C：actual flying time increase-->crashes number decrease，则按照原文，调整课程，加强实战练习可以降低事故数量
D：Lack of actual flying time-->crashes，则调整课程即是将条件取非，使之成为sufficient actual flying time，不能推出降低事故数量啊

首先是主观臆想错误：实际飞行训练时间可能可以降低人为技能缺陷造成的飞行事故（注意只是一个必要条件，不一定是充分条件），但并不能保证全部飞行事故数量的下降，毕竟还有1/3其它的原因。所以你的推理是没有保证的。

其次是假设题的验证是对选项取反，你怎么对原文的推理取反了。

同意你说的对D取非可判断为正确答案
但是对于C，AA if BB可写为BB-->AA的形式，则BB为充分条件，这样判断错在哪里？

如果对C取非，应该是“增加实际飞行时间不会降低事故数量”，为什么不能推翻原命题呢？

C实际为无关项

1。To address this problem中的problem指的是 pilot error ，而不是plane crashes。这是最关键的，也是为何C为无关项的关键原因。PROGRAMS的设计和最后的评价都是针对解决PILOT ERROR问题的。而不是解决plane crashes问题的，故和PLANE CRASHES无关。

I agree D is correct.  But what's wrong with A?

Is that because A is 无关 choice?  The issue here is: to solve pilot error, either flying time or classroom, both of them are part of training program?