he___the display for several mimutes before re-entering his shop.

题目

he___the display for several mimutes before re-entering his shop.
a) was gazing at
b) gazed at
c) had gazed at
d) had been gazing at
选择哪一个,及为什么

答案

选B
因为从句中省略了主语和谓语,过去完成时通常都要和一般过去式形成对比.从句是re-entering,没有表现出过去时的用法,因此前面不宜使用过去完成时.