大全Ⅰ-18死活想不通

18.   Critics of sales seminars run by outside consultants point out that since 1987, revenues of vacuum cleaner companies whose employees attended consultant-led seminars were lower than revenues of vacuum cleaner companies whose employees did not attend such seminars. The critics charge that for vacuum cleaner companies, the sales seminars are ill conceived and a waste of money.

Which of the following, if true, is the most effective challenge to the critics of sales seminars?

       (A) Those vacuum cleaner companies whose sales were highest prior to 1987 are the only companies that did not send employees to the seminars.

(B) Vacuum cleaner companies that have sent employees to sales seminars since 1987 experienced a greater drop in sales than they had prior to 1987.

(C) The cost of vacuum cleaner sales seminars run by outside consultants has risen dramatically since 1987.

(D) The poor design of vacuum cleaner sales seminars is not the only reason for their ineffectiveness.（A）

(E) Since 1987, sales of vacuum cleaners have risen twenty percent.

谢谢

请教版主，这一题是否可由公司参加sales
seminar之前后效果作比较，才可以推得有没有效？因为A公司跟B公司作直接比较，不一定公平，可能某一个公司已经是龙头，另一个还是小角色。

(A) Those vacuum cleaner
companies whose sales were highest prior to 1987 are the only companies that did
not send employees to the seminars.没去不代表没效，就好像我还没看这部电影，不代表他不好看。

(B) Vacuum cleaner companies
that have sent employees to sales seminars since 1987 experienced a greater drop
in sales than they had prior to 1987. 这个支持本文

(C) The cost of vacuum
cleaner sales seminars run by outside consultants has risen dramatically since 1987.
Sales seminars的成本是无关讨论

(D) The poor design of
vacuum cleaner sales seminars is not the only reason for their ineffectiveness.
我觉得这个有点落井下石，算支持本文，就是seminars烂，但是还有更烂的原因让销售不好。（A）

(E) Since 1987, sales
of vacuum cleaners have risen twenty percent.是否暗示参加者的公司有进步，造成整体的进步。因为如果进步的原因不是因为这个研讨会，而是他因，就变成无关的选项。

A

文章通过比较自从1987年来，参加seminar和不参加的seminar的公司的收入，比较得出，不参加依然有比之参加收入要高

A说，文章中所提出的比较中，那些不参加seminar的公司在1987年前，已经有最高收入了，那么就不能说是因为seminar浪费，而是起点不同。

这个题要好好体会一下，一眼未必看得出答案。

谢谢版主的回答，后来我想想

1.     
得要参加的人，才能比较
        →
        比较对象一致

2.     
参加seminar之前或之后的差距→
        比较基准一致

所以要weaken，只要1或2任一条有被推翻，就可以达到效果。是否可以这样推理呢？

我觉得不能推翻你的第一条，因为第一条也是题目中给的假设，只有哦它成立的前提下，你才能去考虑

其他的结果，只能是第二条！