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.
key is D. Why not E? Weaken题型直接削弱A,A不可行或A没有意义，本题即production could not continue.
thanks.作者: lohashilda 时间: 2013-4-27 21:04
注意原文的结论continued production of the drug must inevitably lead to the ibora’s extinction。
很明显是继续生产这个药，而这个药只能从the bark of the ibora中获得，所以持续生产就意味着继续消耗the bark of the ibora，与它在什么地方没有关系。所以E是无关选项。作者: sunshinemuji 时间: 2013-4-28 06:39
谢谢lohashilda！
可是还是不太明白，如果A是continued production of the drug，B是ibroa's extinction，那么我直接说由于ibora inaccessable，A根本不成立，不就已经削弱了命题么？
我也想请教一下，在OG对E的解释是这样说的“Finally, if th eibora is lagely inaccessible, this bears on the question of whehter production of the drug could continue, not on what would happen if it idid continue”
不是很明白为什么说E是 this bears on the question of whehter production of the drug could continue,
更进一步的说，因为造药使得ibora灭绝，要削弱这个argument还是应该从造药不能使得ibora灭绝来着手。E说的根本就是以后没法造药，但是还是有ibora存在，是不会出现结论的情况，但问题是这个跟argument无关啊，不是基于这个argument的。OG的解释Finally, if th eibora is lagely inaccessible, this bears on the question of whehter production of the drug could continue, not on what would happen if it idid continue说的大概就是这个意思。作者: zhanghaolin 时间: 2013-5-13 18:24
