请问og-29, 谢谢

sunshining

29. 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.
10
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.

选C，我怎么看不太明白呢？肠胃病的人少了，officials认为是因为水的质量改善了。

C说医疗进步导致被诊断的人多了。多和少是两回事吧，网上说是他因削弱，我怎么没看明白呢？

哪位讲讲吧，谢谢了

tweib

以下是引用sunshining在2004-9-26 6:51:00的发言：

29. 原文是：The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year,

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.

三处划红线的部分看懂意思

sunshining

呵呵，明白了，谢谢，没注意到那么细