选择合适的句子填空

A. But you can feel it. B. Do you know anything about air? C. Because it can keep us alive. D. It also has no smell or taste. E. It has no colour or shape.

T=Teacher   S=Student

T: Hello, boys and girls. Today we are going to talk about air.

SI: Yes. I think I know something about air.

T: You're right.

S2: Excuse me, can we see it or feel it?

T: You cannot see it. It is everywhere.

S3: Why is it so important to us?

T:

Ss: That is amazing. We should keep the air clean.