5.―Have you handed in your schoolwork yet? 　―Yes I have. I guess it now. A. has gradedB.

问题补充：

5.―Have you handed in your schoolwork yet?

―Yes，I have. I guess it now.

A. has graded

B. is graded

C. is being graded

D. is grading

答案：

A. has graded

B. is graded

(答案→)C. is being graded

D. is grading

解析：now暗示该空表示“现在正在被打分”，因此应填现在进行时被动语态动词形式is being graded。