求助: OG11 紫皮书 020

minzhenyuan

20. 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 10 years ago.

这个题,C固然是正确的, 但是为何A就不对?  请各位NN帮忙看一下

谢谢

小佳

lz注意一个词，“improved”。这些water-treatment plants什么时候建的不重要，重要的是它们条件是否"improve"了。

minzhenyuan

可问题是sanitary conditions 是在今年才有起色的,以前几年是不行的.water-treatment plants是几年前建的,就可以说明water-treatment plants不是sanitary conditions 改善的原因.

个人认为这个选项也是可以的,大家认为呢?

Colx

题目中说的是 sanitary conditions at water-treatment

new water-treatment plants 未必有 improved sanitary conditions ，前几年是建了些工厂，没有起作用可能是sanitary conditions 没有改善

minzhenyuan

感谢

现在清楚了