请教Prep08的一个假设题

FloraZhang1228

73.   Early in the twentieth century, Lake Konfabecame very polluted.  Recently fishpopulations have recovered as release of industrial pollutants has declined andthe lake’s waters have become cleaner. Fears are now being voiced that the planned construction of an oilpipeline across the lake’s bottom might revive pollution and cause the fishpopulation to decline again.  However, atechnology for preventing leaks is being installed.  Therefore, provided this technology iseffective, those fears are groundless.

The argument depends on assuming which ofthe following?

(A)    Apart from development related to the pipeline,there will be no new industrial development around the lake that will createrenewed pollution in its waters.

(B)    There is no reason to believe that theleak-preventing technology would be ineffective when installed in the pipelinein Lake Konfa.

(C)    The bottom of the lake does not contain toxicremnants of earlier pollution that will be stirred into the water by pipelineconstruction.

(D)   Damageto the lake’s fish populations would be the only harm that a leak of oil fromthe pipeline would cause.

(E)    The species of fish that are present in LakeKonfa now are the same as those that were in the lake before it was affected bypollution.

Prep08的一道题，这题答案选C，但感觉B也是对的啊，属于搭桥题，取反也能削弱选项。

谢谢大家！

alzn2765

因果推理找假设
前提（因）：technology for preventing leaks is being installed+this technology is effective
结论（果）：fears of pollution are groundless.
因--->果
注意因果之间有一个gap: 前提中之说这个“pipe不会leak”，结论说的是“不会有pollution”。只有pipe leak一种情况可以导致pollution吗？显然不是。为了让结论成立，我们就要排除其他可能导致pollution的情况。
所以C是正确答案。

题干说provided this technology is effective，已经给出了结论成立的必要条件。B就是这个假设内容重复了一遍，等于啥也没说。所以B错。

退一万步说，假设我现在告诉你BC都没错，你是不是也得选一个？一道题不能选两个吧？B是重复选项已经说过的内容，C是跟结论有关，但是与题干不一样的内容。你想想assumption的定义是什么？assumption一定是结论成立的必要条件，同时又是没说出来的那个条件吧？说出来的就是前提Premise了。那你说选哪个？

FloraZhang1228

alzn2765 发表于 2016-2-20 23:11
因果推理找假设
前提（因）：technology for preventing leaks is being installed+this technology is eff ...

谢谢大神的透彻解析！！没注意题干里的“provided this technology is effective”