A: Tom, it seems that you are not happy.

B: Yes, a little.

A: why?

B: I see someone is cutting the trees.

A: Oh, Cutting the trees is a very bad behavior.

B: Yes! Trees are important for us, and trees can keep the earth from washing away and make the air cleaner.

A: Besides, the more trees we plant, the better our climate will become.

B: But now more and more trees are cut and the forests become smaller and smaller.

A: So we must protect and plant trees.

B: Why don't we plant some trees now?

A: Good idea. Let us go!