—May I go outside and play for a while Dad?—No you can’t your homework is being done.A.

问题补充：

—May I go outside and play for a while, Dad?

—No, you can’t your homework is being done.

A. until

B. as

C. before

D. the moment

答案：

A. until

(答案→)B. as

C. before

D. the moment

解析：考查连词;A. until直到B. as 当…时候，因为C. before在…之前，D. the moment一…就，句意：--我可以出去玩一会吗？--不，你不能，因为你正在做作业。选B。