(2010上海29)—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
答案:C
解析:考查虚拟语气。此处表示和过去事实相反的情况,应该用“should have + 过去分词”结构,表示“本来应该做而未做”。
句意:——对不起,史密斯教授。我昨天没有完成这项作业。——哦,你本应该昨天做完的,因为昨天是最后期限。