It ______ be the postman at the door. It
问题:
It ______ be the postman at the door. It's only six o'clock.[ ]
A. mustn't
B. can't
C. won't
D. needn't
It ______ be the postman at the door. It's only six o'clock.[ ]
A. mustn't
B. can't
C. won't
D. needn't