---May I go and play with Tom this afternoon, mum?
---No．You can’t go out your homework is being done．
A. until
B. after
C. before
D. as
网友回答
A. until
B. after
C. before
(答案→)D. as
解析：“妈妈，今天下午我可以和汤姆去玩吗？”“不行，你不能出去因为你正在做作业。”A．until 直到 B．after之后 C．before 之前 D．as因为，答案D。