--- Listen! David is talking happily wit
问题:
--- Listen! David is talking happily with his mother in the next room.
--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.
A.should
B.must
C.can’t
D.mustn’t
--- Listen! David is talking happily with his mother in the next room.
--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.
A.should
B.must
C.can’t
D.mustn’t