选择句子，补全对话。

A: Welcome to our school. This is the teacher's office. This is my classroom.

B: 1_____

A: Forty-five.

B: Do you have a library?

A: Yes.

B: Do you have lunch at school?

A: 2_____

A: Look! This is our playground.

B: 3_____

a. Cool! Your school is beautiful.

b. How many students are there in your class?

c. Yes. The canteen is on the first floor.