—Is Jack on duty today? —It be him. It is his turn tomorrow.A. mustn’t B. won’t C. can’t

问题补充：

—Is Jack on duty today? —It be him. It is his turn tomorrow.

A. mustn’t

B. won’t

C. can’t

D. needn’t

答案：

A. mustn’t

B. won’t

(答案→)C. can’t

D. needn’t

解析：情态动词表示推测,肯定性推测用must,否定性推测要用can’t.