-----Did Mary e to the party?
---I don’t know．She while I was out．
A. may have e
B. must have e
C. might e
D. could e
网友回答
(答案→)A. may have e
B. must have e
C. might e
D. could e
解析：这题考查情态动词的完成式的用法：从第一句话知道是指过去的事，从-I don’t know，知道是可能已经来了。用may have e，A项正确。