A: Hello Jack called you last night but you weren't in
B: Oh I went the TV station of our city.
B: I took part in a talk show.
B: It was about how to be a greener person.
A: Sounds great! It is very important for everyone to be a greener person, isn't it?
A: What should we do to be a greener person?
B: We can obey (遵守) the three R's.
A: The three R's?
B: Reduce, reuse and recycle.
A: Oh, I see. It's very kind of you to tell me so much.
B: It' stay pleasure.
A. What are they?