OG10的一道逻辑题（含分析）

weimmary

The number of people diagnosed as having a certain intestinal disease has dropped

significantly in a rural county this year, as compared to last year. Health officials attribute this

decrease entirely to improved sanitary conditions at water-treatment plants, which made for

cleaner water this year and thus reduced the incidence of the disease.

Which of the following, if true, would most seriously weaken the health officials’ explanation for

the lower incidence of the disease?

A. Many new water-treatment plants have been built in the last five years in the rural county.

B. Bottled spring water has not been consumed in significantly different quantities by people

diagnosed as having the intestinal disease, as compared to people who did not contract

the disease.

C. Because of a new diagnostic technique, many people who until this year would have been

diagnosed as having the intestinal disease are now correctly diagnosed as suffering from

intestinal ulcers.

D. Because of medical advances this year, far fewer people who contract the intestinal

disease will develop severe cases of the disease.

E. The water in the rural county was brought up to the sanitary standards of the water in

neighboring counties ten years ago.
   

答案是选C。相当郁闷，为什么不选A呢？既然last five years已经有plants，更加说明不管plants的事情啦。

OG给的标准解析如下：

The health officials’ explanation assumes that the decrease in the number of people diagnosed

with the disease accurately reflects a diminution in cases of the disease. By pointing out that

this assumption is false, C undermines the officials’ explanation and thus is the best answer.

Since A supports the view that sanitary conditions have been improving, it tends to support the

officials’ explanation. B also tends to support the officials’ explanation, because it eliminates a

factor that might have differentiated between those contracting and those not contracting the

disease and thus rules out an alternative explanation. The reduction of the severity of the

diagnosed cases does not bear on the officials’ explanation. So D is not correct. Since the

standards in neighboring counties might themselves have been inadequate, E does not

weaken the officials’ explanation.

[此贴子已经被作者于2009-4-17 16:55:44编辑过]

h5641

個人淺見:

題目已經給了我們 說明 診斷的降低是因為 環境衛生 或 水質的進步

但是 答案A, 也是站在同一個角度來推論這個結果, 因此跟答案C比較起來, 更像是強化原推論.

因此 C 有給出新的因素 來 Weaken 原來的推論.

你再想想看一下  別鬱悶~ ^__^