问题补充：
--- I did not see your elder brother at the lecture yesterday.
---You him, since he went to see Chinese Zodiac---Jackie Chan’s 100th movie.
A. mustn’t have seen
B. couldn’t have seen
C. shouldn’t have seen
D. needn’t have seen
答案：
A. mustn’t have seen
(答案→)B. couldn’t have seen
C. shouldn’t have seen
D. needn’t have seen
解析：句意：--昨天在报告会上我没有看见你的哥哥。--你不可能见他，因为他去看成龙的第100部电影中国的十二生肖。shouldn’t have done过去不应做的而做了；needn’t have done过去没必要做的而做了；couldn’t have done过去不可能做某事。must表推测时不能用在否定句，故选B。
