OG-29题

xuxiaoquan

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.

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.

29.

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.

请教各位，为什么选C?

    谢谢！

leighyao

OG has said very clearly.