--- Where is Jack?--- He football on the playground with those AFS students but I am not

问题补充：

--- Where is Jack?

--- He football on the playground with those AFS students, but I am not sure.

A. must be playing

B. must have played

C. may be playing

D. may have played

答案：

A. must be playing

B. must have played

(答案→)C. may be playing

D. may have played

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