[讨论]请教一道逻辑题

zijing4546

    

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 trees 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）

    

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

D和E我觉得都成,一个说多种,一个说砍不到.......

zijing4546

没大侠帮忙,是太简单不屑呢,还是太难没人会......

frances77

         S                   N 

Continued production----->Extinction 

A->B要削弱，应该A－－－>～Ｂ，（Ｄ）即Ａ－－＞～Ｂ，而（Ｅ）实则～Ａ－－＞～Ｂ

所以选Ｄ不选Ｅ     

phoenixfr

E不对!E是反对前提.

E说生长在无法接近的地方就是再说没法进行continued production of the drug .

削弱的时候是要承认前提反对结论(feifei的话),所以你这个不对!

phoenixfr

用楼上的话说,就是～Ａ－－＞～Ｂ并不对A->B这个推理的合理性构成威胁.

zijing4546

多谢!!!!!