问题补充:
---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
答案:
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。