---Sorry, Professor Smith. 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
网友回答
A. must
B. mustn’t
(答案→)C. should
D. shouldn’t
解析：本题考查的是虚拟语气。此处表示和过去事实相反的情况，应该用should + have + 过去分词。本来应该做，而未做。选C。