当废水量较小时，可考虑选用（）沉淀池。

A.竖流式

B.平流式

C.辐流式

D.曝气沉砂式

根据给出的汉语进行填空。

1. 1 have to _____the dog _____a walk(遛狗)and _____ _____ _____

(买东西)．

2. My grandfather had to get up at 5 a.m to _____ _____(劈柴) and_____ _____

_____(生火)

for the breakfast.

3. Then my grandfather had to_____  _____ _____(喂家畜)．