- Tom, where is your father?- I’m not sure. He _______ in his office.
#74723
A
must be
B
may be 
C
maybe
D
need be
推荐题目
I want to open the door, but it _____ open.
#62889
A
couldn’t
B
won’t
C
wouldn’t
D
mustn’t
Their answers are exactly the same. One of them ___ from the other.
#62605
A
must copy
B
must have copied
C
should copy
D
should have copied