Mr Jackson: Can anyone tell me what you can see in the first photo?

Betty: There’s a factory, and it’s causing a lot of pollution.

Mr Jackson: Correct. So what can we do about it?

Tony: Well, there should be some rules to stop the pollution.

Mr Jackson: What about the second photo?

Daming: It’s a recycling centre. Waste products such as glass and paper can be recycled there.

Mr Jackson: Good. Why do we need to do that?

Lingling: To save energy, I guess.

Mr Jackson: Great!