My sister met him at the Grand Theatre yesterday afternoon,so he

My sister met him at the Grand Theatre yesterday afternoon,so he ______ your lecture.
A、couldn’t have attended
B、needn’t have attended
C、mustn’t have attended
D、shouldn’t have attended
【正确答案】：A
【题目解析】：couldn’t have done: (过去)不可能做某事; needn’t have done:本来不必做某事;mustn’t have done:一定未做过某事： shouldn’t have done:本不该做某事。根据提供的情境My sister met him at the Great Theatre表明他不可能参加讲座。答案是：A。