When you get the paper back,pay special attention to what .
A. have marked
B. have been marked
C. had marked
D. had been marked
网友回答
A. have marked
(答案→)B. have been marked
C. had marked
D. had been marked
解析：现在完成时表示已经完成的动作或存在的状态。根据句意可判断出当试卷发下来时，已经批改，所以要用现在完成时。根据paper和mark的关系可判断出要用被动语态。表示被批改。过去完成时表示一个动作或状态在过去某一时间或动作之前已经完成或结束，即“过去的过去”；也可以指过去的动作延续到过去的某个时刻。选项A和C都是主动语态，所以是错误的。