17 Mary ________ his homework late last night, so she felt sleepy in class this morning.
A: must do
B: must be doing
C: must have been doing
D: must have been done
A: must do
B: must be doing
C: must have been doing
D: must have been done
举一反三
- Had it rained last night, the road _____ wet now. A: would be B: must be C: would have been D: must have been
- Somebody ______ here only this morning. A: must be B: can be C: must have been D: should have been
- Lots of homework _____, I must do it now. A: done B: doing C: to do D: is done
- She _______ fifty or so when I first met her at a conference. A: had been B: must be C: has been D: must have been
- Mike looks so sleepy in the class; he ______ up last night. A: must stay B: should have stayedC. must have stayed D. is sure to stay