— It _______ be Jack who is in the office.
— No, it _______ be him. I saw him off at the airport half an hour ago.
A. can’t ; can’t B. must; can’t
C. must; mustn’t D. may; mustn’t
— It _______ be Jack who is in the office.
— No, it _______ be him. I saw him off at the airport half an hour ago.
A. can’t ; can’t B. must; can’t
C. must; mustn’t D. may; mustn’t
B
must表推测只用于肯定句;在否定句和疑问句中用can。