Listen and read.
Lan: Hi, Dad.
Mr Tan: Lan, what are you doing? It's pretty late now.
Lan: I'm doing a project on energy sources. But I don't quite understand what energy is
Mr Tan: Well, it's power that we use to provide us with light, heat or electricity.
Lan: Oh. Where does it come from? Mr Tan: It comes from many different sources like coal, oil, natural gas.... We call them non-renewable sources
Lan: Can it come from the sun, wind or water too?
Mr Tan: Yes, it can. We call those types of energy renewable sources because we cannot run out of them. Renewable means we can easily replace them.
Lan: I get it now.
Mr Tan: You know, some types of energy are cheap and easy to use, but others are more expensive and harder to find…