—Listen! Is that Kate singing in the room?
—No. It _____ be Kate. She hasn't been back from Beijing yet. [ ]
A. must
B. can't
C. mustn't
答案:B
—Listen! Is that Kate singing in the room?
—No. It _____ be Kate. She hasn't been back from Beijing yet. [ ]
A. must
B. can't
C. mustn't
答案:B