Question

His essay, ______ many times, was brief and to the point and therefore won the first prize in the writing competition.

  A. polishing up                                         B. having polished up   

  C. to be polished up                                   D. having been polished up

Answer 1

D

解析:

考察非谓语动词的用法。由于polish up和His essay之间的逻辑关系为动宾关系，非谓语动词的动作发生在主句谓语动词之前，所以应用完成式分词的完成被动形式作原因状语。