—I knocked but nobody answered the door. ----They _____asleep then and didn’t hear you.
#88169
A
must be
B
should be
C
must have been
D
should have been
推荐题目
———It was a green dinner. _______ ———Thanks. But it really only took an hour.
#87721
A
You must be tired.
B
I enjoyed it very much.
C
You must have spent all day cooking.
D
I have never had it before.
 Were it not for the snowy weather, we ________ all right. 
#89373
A
would be  
B
would have been
C
were
D
may be
--- How much shall I pay for the phone call? --- You ________. This is free of charge. 
#87096
A
shouldn’t
B
can’t
C
don’t have to
D
mustn’t