It's the frist time that I( )asleep then.A.must be B.must have been C.should be D.should have been为什么

问题描述:

It's the frist time that I( )asleep then.A.must be B.must have been C.should be D.should have been
为什么

Amust be 表示对将来的猜测,与原句不符Bmust have been此句型用于表示对过去的肯定推测C should be 用于虚拟语气,意思指“本应该在/是...”D should have been是“本应该已经”,但是事实上没有这样做,而且事情发生在过去。
所以选择B合适

B主+序数词+time that +that_分句,that 后一律用完成时当主句动词为is/will be 时,that 分句动词一律用现在完成时,引导词that 可以省略,如:it's the first time i've been here 当主句动词为was 时,that 分句动词...