—Hurry up, Mum. The lights are turned on. Dad has been back.
—It be him. He has gone to Shanghai.
A. must
B. can’t
C. mustn’t
D. may
网友回答
A. must
(答案→)B. can’t
C. mustn’t
D. may
解析：must必须，一定；can’t不能；mustn’t禁止；may可以。句意：快点，妈妈。灯已经亮了。爸爸回来了。——不可能是他。他已经去了上海。结合语境可知选B。