Where is Jack? I can’t find him anywhere.He his homework upstairs.A. might have d

问题补充：

--- Where is Jack? I can’t find him anywhere.

--- He his homework upstairs.

A. might have done

B. must have done

C. might be doing

D. must do

答案：

A. might have done

B. must have done

(答案→)C. might be doing

D. must do

解析：本题考查情态动词表猜测的用法。结合语境Where is Jack?可知说话人想知道Jack现在在哪，谈论的是现在的事，排除AB; “在楼上做作业”应是正在进行，排除D。