削弱题,前提到底能不能被否定?

woshilaoyumi

68. A drug that is highly effective in treating many types of infection can, at present, be obtained only from the bark of the ibora, a tree that is quite rare in the wild. It takes the bark of 5,000 tree to make one kilogram of the drug. It follows, therefore, that continued production of the drug must inevitably lead to the ibora’s extinction.

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

(A) The drug made from ibora bark is dispensed to doctors from a central authority.

(B) The drug made from ibora bark is expensive to produce.

 (C) The leaves of the ibora are used in a number of medical products.

(D) The ibora can be propagated from cuttings and grown under cultivation.

(E) The ibora generally grows in largely inaccessible places.

根据NN的精华贴:E的致命之处在于原文的结论是有前提的：continued production of the drug 。即结论是在能继续生产的前提下得出结论的。所以如果如E所说的I长在找不到的地方，则无法继续生产，也即结论的前提没满足，不满足结论的条件，更谈不上削弱结论，因为不能继续生产是另外一个问题，不是结论谈论的问题，应该是无关选项。

可是再看这题:

114. The more frequently employees take time to exercise during working hours each week, the fewer sick days they take. Even employees who exercise only once a week during working hours take less sick time than those who do not exercise. Therefore, if companies started fitness programs, the absentee rate in those companies would decrease significantly.

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

(A) Employees who exercise during working hours occasionally fall asleep for short periods of time after they exercise.

(B) Employees who are frequently absent are the least likely to cooperate with or to join a corporate fitness program.

 (C) Employees who exercise only once a week in their company’s fitness program usually also exercise after work.

(D) Employees who exercise in their company’s fitness program use their working time no more productively than those who do not exercise.

(E) Employees who exercise during working hours take slightly longer lunch breaks than employees who do not exercise.

答案选B. 这不是典型的否定前提吗?

类似的题目还有很多.我很郁闷的,刚开始做CR 时候什么都不懂,正确率却还不错,可以对80%.好好总结了一遍以后反而错的更多(50%).还做的更慢了.555555 现在不知道如何复习下去了

[此贴子已经被作者于2006-8-27 10:51:40编辑过]

woshilaoyumi

自己顶

gonghao

in the first question given,the conclusion is clear defined.The trees will extinguished when we need large amount of drug result from the the trees.

If choice D is true then the conclusion will be undermined without any doubt.In choice E,the choice wants to say that since the difficulties in accessing to the trees,the trees will eacape the fate of extinguishing.But it does not strike on the point of the argue.In the paragaph above the reason is that the only source of the durg is the tree,so if demand of drugs increases darmatically,trees will be cut down no matter where they located.So choice E does not make any of sence.

In the number 114 question listed above,the evidence shows that the rate of getting sick among people who do exercise is lower that that among people who nver do.Then the company want to launch a pragam of exercise so that the rate of absence will decrease prospectively.The permise here is everybody will get involve in the program pushed by the company so that choice B point it out directly and then weaken the conclusion.

So weaken can be generalized in serval patterns of answer.First is to dissociate the reason from the result,or to depart the conlusion and permise.Second is to find out other reasons that will cause into the conclusion logically.Third,,to find out the errors in logical sequence.Fouth is to focus on the accurate of the data used in the argument.Five is to get the conclusion unexclusively to weaken the argument.

premise can be weaken and of course ,that is one of ways to weaken the argument. 

[此贴子已经被作者于2006-8-28 15:18:04编辑过]

woshilaoyumi

thank you very much.还有一个问题.

没归纳之前做逻辑正确率不错.归纳总结了之后反而做题时不知所措了.

我这样的情况是否不要归纳总结?

gonghao

总结是必须的

但是不要被机械的总结规律所束缚，总结是帮助你了解ETS的习惯和思路，以及典型的错误选项和争取选项。现在的GMAT考题越来越活，只根据规律来做题会吊入ETS的陷阱，重要的是弄清题目讲的重点是什么。规律是我们心中的大方向，绝不是具体的正确答案。

woshilaoyumi

有道理.谢谢斑竹