--- He worked out such different questions at a very young age.--- Oh, he ______ a very smart student then.
#63131
A
could have been
B
should have been
C
might have been
D
must have been
推荐题目
I was really anxious about you. You____ home without a word.
#62986
A
mustn’t leave
B
shouldn’t have left
C
couldn’t have left
D
needn’t leave
 —Must we finish the project in a month?—No, you _______. 
#74870
A
mustn’t
B
needn’t
C
can’t
D
don’t