用括号中所给词的适当形式填空。

1.___________ (be)Jim and Lily happy?

2.____________( not be)  late again.

3.Look at_______. Are they happy? (their)

4. -Where's your classroom?

   -It's on the ______ (one) floor of that building.

5.This is my English book.It's not ________________(her)

下列哪项措施可适当减少鱼缸的换水次数（）

A.鱼缸中放入一些金鱼藻

B.改用凉开水养鱼

C.鱼缸中放入一些泥沙

D.改用纯净水养鱼