问题

Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
A:can; must
B:can; may
C:must; can
D:may; must
B:can; may
C:must; can
D:may; must
正确答案是:
同类题型
You should never base anything on a theory that _________ impractical in practice.
Look at the trouble I’m in If only I ________ youradvice
I’m quite nervous about tomorrow’s oral English Test. –_________.
It’s bad _______ you to eat too much __________ you’re too fat.
She asked the man _______ it was true he had been a soldier before.