明天上战场，请教一道pREP逻辑题

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Some airlines allegedly reduce fares on certain routes to a level at which they lose money, in order to drive competitors off those routes.  However, this method of eliminating competition cannot be profitable in the long run.  Once an airline successfully implements this method, any attempt to recoup the earlier losses by charging high fares on that route for an extended period would only provide competitors with a better opportunity to undercut the airline's fares.

Which of the following, if true, most seriously weakens the argument?

(A) In some countries it is not illegal for a company to drive away competitors by selling a product below cost.

(B) Airline executives generally believe that a company that once underpriced its fares to drive away competitors is very likely to do so again if new competitors emerge.

(C) As part of promotions designed to attract new customers, airlines sometimes reduce their ticket prices to below an economically sustainable level.

(D) On deciding to stop serving particular routes, most airlines shift resources to other routes rather than reduce the size of their operations.

(E) When airlines dramatically reduce their fares on a particular route, the total number of air passengers on that route increases greatly.

为什么是B，可否解释一下？谢谢回复

嘿嘿，又是一道和经济学有关的题，偶喜欢。

这个题很狡猾的。我要是不看答案就直接选E了，因为它符合经济学常识：在成本基本不变的情况下，要保证收益不变或增长，票价的降低，可以通过销量大增来弥补。

可是题中并未谈到销量的问题，而是关注在竞争者方面（脑海中顿时出现博弈论的纳什均衡，呵呵，条件反射），这样用经济常识解题反而出错！所以只能用逻辑推理了。

A。C。D。很容易排除。B太隐蔽了，不过几个逻辑要素都包含了，而且符合Weaken题型的要求。题中论点的支持理由是by charging high fares-only provide competitors with a better opportunity, B直接就否定了提价这种可能，“一旦降价，由于竞争，只能一降再降”——就是说决不会有提价这种可能，所以成立。

顺便说一下，这个航空公司领导的脑袋有点进水，光想着把客户弄到手就狠宰，又怕别的公司竞争。可是仔细一想，国企大多如此，中国特色吧：）

Always find out logical structure first, then everything is simple. Most so-called "difficult questions" just distract us from finding the logical structure.  See the following:

Premise 1:      A (reduce fares) ==> B (drive competitors off; fares increase) + C (Lose money)

Premise 2:      No A (increase fares)

Conclusion:     No A (increase fares) ==> No B (competitors back; fares decrease) + no C (increase profit)

        

Assumption:  If  No A, then must No B.

Weaken: When no A happens, no B does not happen.

不喜欢公式化的推理

从意思上来说

题目的结论是 一家利用低价排挤竞争对手的航空公司在弥补损失阶段很有可能会被其他的公司用同样的方式排挤

所以B很明显地驳斥了说 这家航空公司不会嘛 因为他还会用同样的手段

so.....

我也感谢楼上各位的提醒：）

有时候感觉自己逻辑提高不了，就是因为缺少严格的逻辑思维。三楼Whitney同学的建议很正确，大家都要注意走出惯性思维的误区。