1. 给下列句子选择合适的答语。

A. No．It's on the first floor.

B Thank you.

C. Yes，it is．   

D. It's next to my classroom.

1. （1） Is this a library?
3. （2） Where is the teachers' office?
   
5. （3） Here's my homework．
7. （4） Is it on the second floor?