---Sorry, sir. I can't answer this question.
---Well, you are supposed this part of history.
A. reading
B. to be reading
C. to read
D. to have read.
网友回答
A. reading
B. to be reading
C. to read
(答案→)D. to have read.
解析： 句意：--对不起，先生，我不能回答这个问题。--哦，你应该读过这个部分的历史的。Be supposed to have done“过去本应该做…而没有做”，这是一种虚拟语气的表达，所以选D。