— Shall Brown come and play computer games?
— No, ________ he has finished his homework.
A:when
B:if
C:unless
D:once
课内阅读。
小鸭子正在水里捉鱼,忽然,听见小公鸡喊救命。他飞快地游到小公鸡身边,让小公鸡坐在自己的背上。小公鸡上了岸,笑着对小鸭子说:“鸭子哥哥,谢谢你。”