—Sorry Mr. Wang. I didn’t finish the assignment yesterday. Oh you have done it as yeste

问题补充：

—Sorry, Mr. Wang. I didn’t finish the assignment yesterday.

Oh, you have done it as yesterday was the deadline.

A. must

B. mustn’t

C. should

D. shouldn’t

答案：

A. must

B. mustn’t

(答案→)C. should

D. shouldn’t

解析：考查情态动词用法must have done一定做了某事； Should have done本应该做某事实际上却未做。句意：你本应该昨天就完成的，因为昨天是最后期限。