请根据本单元的知识完成对话。

　　A: What’s this ________ ________?

　　B: It's ________ ________ ________.

　　A: Is it your computer game?

　　B: Yes, ________ ________.

　　A: And what's that? Is it your eraser?

　　B: ________, it is.

　　A: How do you spell eraser?

　　B: ________.

　　A: Is that your notebook?

　　B: ________, ________ my pencil case.

根据句意和首字母，用本单元的单词填空。

The air is so nice and clean in c　　.

根据句意和首字母，用本单元的单词填空。

What are you doing for v　　?

根据句意和首字母，用本单元的单词填空。

Pierre is going to Canada's Great Lakes r　　.

根据句意和首字母，用本单元的单词填空。

I'm b　　 my sister.