prep2-15

15.   (25986-!-item-!-188;#058&002914)

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.

正确B

搜了前人的讨论，还是没搞懂为什么D错。原文说However, this method of eliminating competition cannot be profitable in the long run.问削弱。可以理解B对的，但为什么D不对呢？

weaken 的应该是
        provide competitors with a better opportunity to undercut the airline's fares.  这个结论。只有B 提供了 new competitors不会 emerge的理由，就是competitors的executives generally believe 曾经用降价手段的company 极有可能再次用这个手段，那这个 new competitors 就有可能再一次被drive competitors off those routes。

D irrelevant.

B、D 俩选项比较下吧。

D里用了most，就没有B削弱来的彻底了

我也选了d，不过既然airlines可以shift resource to othter routes,那么他们也能shift resource back对吗。所以b更加安全一点

I would say, D could not weaken the conclusion.

D says that "most airlines shift resources to other routes rather than reduce the size of their operations", but it doesnt mean these airlines would never come back to the routes which become profitable again.

Because the possibility that the competitors may get back into the old routes still exists, the conclusion would not be weakened.