My sister met him in the hospital yesterday afternoon, so he your lecture.
Acouldn’t have attended
Bneedn’t have attended
Cmustn’t have attended
Dshouldn’t have attended
网友回答
(答案→)A. couldn’t have attended
B. needn’t have attended
C. mustn’t have attended
D. shouldn’t have attended
解析：句意：我的姐姐昨天下午在医院见到他了，所以他不可能去听你的演讲。couldn’t have attended表示不可能；needn’t have attended表示过去做了不必做的事情；mustn’t have attended通常没有这种结构；shouldn’t have attended本不应该做某事，而实际做了某事， 选A。