20.   The Asian American History Association receives approximately 1,000 proposals each year from individuals who wish to present papers at its annual meeting. The association’s officers would like to ensure constant standards of quality in the presentations from year to year. The officers have therefore decided to accept for presentation each year only the best 300 papers selected on the basis of the quality of the proposals submitted.

Of the following, the best criticism of the officers’ plan is that the plan assumes that

(A) Professional associations cannot accept all papers submitted for presentation at their annual meetings.

(B) The total number of proposals submitted to the association will remain at approximately 1,000 in future years.

(C) Each proposal submitted to the association deserves to be considered a serious candidate for presentation.

(D) It is difficult to judge the quality of a paper on the basis of the proposal alone.（E）

(E) The best 300 papers submitted to the association for presentation will be of the same quality from year to year.

答案是D，但是我不太明白为什么，以前也作过类似这样的题，只是凭记忆感觉E对，哪位高手能讲讲为什么，谢谢！

假设题，条件取非去验证一下结论是否成立。

E取非结论不能成立，The association’s officers can not ensure constant standards of quality ,therefore......

哎，粗心了，只看了criticism就以为是削弱题就没往后看题目了，原来是

假设题，stupid mistake

thx

of papers could not maintain the quality of themsleves,then the

quality of the meeting couldn't be maintained even though then

benchmark of the proposal is tough.