语法大全987排序236请教

236.     Degler does more than merely summarizing existing research; he constructs a coherent picture of two centuries of studies dealing with the changing roles of women.

(A) Degler does more than merely summarizing

(B) Degler’s study is more than a mere summarizing of

(C) Degler has done more than a mere summarizing of

(D) Degler’s study has done more than summarize merely

(E) Degler does more than merely summarize

答案是E，ABCE显然都不对，但是E中为何不是summarizes呢？