Someone is knocking at the door. It ______ my mother. It's time for her to be back.
A: can be
B: may not be
C: must be
D: mustn't be
A: can be
B: may not be
C: must be
D: mustn't be
举一反三
- Someone is knocking at the door. Who________ it be? A: can B: may C: must D: will
- There is someone knocking at the door. __________ it be Tom? A: Can B: Must C: Should D: Ought
- She was so _____ with her job that she didn’t hear someone knocking at the door.
- "Someone is knocking at the door." "Who can __ be?"
- Must I do my homework at once?-No, you___. A: needn't B: mustn't C: can't D: may not