He must have an accident,or he ( ) here then.

题目

He must have an accident,or he ( ) here then.
A.should have been B.should be C.would be D.were
为什么不选B 怎么看出前半句是过去完成时的?

答案

这是情态动词加完成体的特殊意义
should have done
表示"本应该做某事却未做"
He must have an accident,or he should have been here then.
他一定出事故了,要不然他当时会在这儿了