问题补充：
–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：句意：你的作业交了吗？--是，交了，我猜现在正在被批改。因为时间是now，而且schoolwork和grade是被动关系，用现在进行时的被动，所以选C。
