A:she looks unhappy ( ).anything have happened to her?

题目

A:she looks unhappy ( ).anything have happened to her?
B:I'm not sure,but I guess something () happened.
A May; must have
B Can; may have
C Must; may
D should; might have
请解释每一个选项.

答案

　B　
翻译：她看起来不高兴.她可能出了什么事吗?
——我不确定,但我想可能出了什么事.
can have done“可能做了某事”,用于疑问句或否定句； may have done“可能做了某事”,表示把握较小的推测,用于肯定句.
should have done 表示应该做过某事（在句子中翻译不合适）
must have done 表示肯定做过某事
由I’m not sure看出回答者并不肯定,因此只能选择may have happened