问题描述:
Hardly ___________ the papers on his desk when the door burst open.
A.he collected B.he had collected C.did he collect D.had he collected
选出答案并请说明原因,
那为什么要用过去完成时呢?
A.he collected B.he had collected C.did he collect D.had he collected
选出答案并请说明原因,
那为什么要用过去完成时呢?
问题解答:
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