问题
选择题
My sister met him at Ningbo Grand Theatre yesterday afternoon, so he your lecture.
A．couldn’t attend
B．mustn’t have attended
C．shouldn’t attend
D．couldn’t have attended
答案
答案：D
从上文可知，句子叙述的是已经发生过的事情，故用完成时态，mustn’t have done表示禁止的意思，故选D，以此他不可能参加过你的演讲。