LSAT19/S3/Q15有劳各位高手版主

mzyzhu

T19/S3/Q15. The only plants in the garden were tulips but they were tall tulips So the only plants in the garden were tall plants.

Which one of the following exhibits faulty reasoning most similar to the faulty reasoning in the argument above?

(A) The only dogs in the show were poodles and they were all black poodles. So all the dogs in the show were black.

(B) All the buildings on the block were tall. The only buildings on the block were office buildings and residential towers. So all the office buildings on the block were tall buildings

(C) All the primates in the zoo were gorillas. The only gorillas in the zoo were small gorillas. Thus the only primates in the zoo were small primates

(D) The only fruit in the kitchen was pears but the pears were not ripe. Thus none of the fruit in the kitchen was ripe

(E) All the grand pianos here are large. All the grand pianos here are heavy Thus everything large is heavy

the answer is C, but I confused between A and C. It seems that I have not mastered the nuance between ALL and ONLY. Would some LSAT CR veterans help me out please? Very appreciate.

[此贴子已经被作者于2003-6-14 15:02:38编辑过]

lyricling

原文推理：
(1) plant in the garden --->T   (2)T ---> tall (3) plant in the garden --->tall plant
tall 为T（子集）的特征，但原文推理将其变成了plant(全集)的特征。

(C)All the primates in the zoo were gorillas. The only gorillas in the zoo were small gorillas. Thus the only primates in the zoo were small primates

(1) primtates in the zoo ---> gorillas (2) gorillas in the zoo --->small gorillas (3) primates in the zoo --->small primates
small 是gorillas（子集）的特征，但推理却将small变成了primates(全集)的特征。
注意这里：tall 与small 都是相对概念，集合不同，tall or small的标准就不同。tall 的T或者small的 gorillas（子集）就不一定是tall的plant 或small 的primates(全集)。

再看A：
A)The only dogs in the show were poodles and they were all black poodles. So all the dogs in the show were black.
(1) Dogs in the show ---> poodles (2) poodle dogs in the show ---> black poodles (3)
all the dogs in the show --->balck.
black是个绝对标准，是black的poodles(子集),自然也是black的dogs(全集).

mzyzhu

beautiful!!!