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?

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?
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?

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?
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

你好：为您提供精确解答

翻译为：他肯定是遇到什么事故了，要不然他应该已经在这里了。

明显末尾是采用虚拟的用法，对现在的虚拟，采用should /could /might /would+have done形式。


谢谢，不懂可追问
【烟波】为你解答

这是虚拟语气的对过去的猜测，所以要降一级，为过去完成时