用所给词的适当形式填空

1. Good watches must have good _____(quality).

2. Don't you think the sofa is very _____(comfort) ?

3. How many _____(province) are there in China?

4. Who runs _____(fast) in this class?

5. I speak English _____(badly) than he does.

常用的锅炉的煮炉药剂是（）。

A.氢氧化钠

B.无水碳酸钠

C.磷司螨钠

D.氢氧化钠和磷司螨钠