问题补充：
—Turn off the TV,Jack. your homework now?
—Mum,just ten more minutes,please.
A. Should you be doing
B. Shouldn’t you be doing
C. Couldn’t you be doing
D. Will you be doing
答案：
A. Should you be doing
(答案→)B. Shouldn’t you be doing
C. Couldn’t you be doing
D. Will you be doing
解析：Shouldn’t you be doing your homework now?表示“难道你现在不应该做作业吗？”是一种责备的口吻。根据答语，应选B项。Should you be doing your homework now?表示“你现在应该做作业吗？”暗示现在不应该做作业。所以是错误的。
