问题补充：
—What did you say to your sister? I saw her crying in the room.
— It my fault. I just said hello to her when I met her, nothing else.
A. must have been
B. can’t have been
C. oughtn’t to be
D. should have been
答案：
A. must have been
(答案→)B. can’t have been
C. oughtn’t to be
D. should have been
解析：考查情态动词。Can’t have done不可能做某事。句意：——你对你姐姐说了什么？我看到她在房间里哭。——不可能是我的错吧。当我遇到她的时候，我只是向她问候了一下，其它什么也没说。故B正确。
