A: Hey , Frank, 

B: Pretty good.

A: Did you have fun last weekend?

B:   I went to the old people's house with my friends and have a good time

A: Wow, What did you do there?

B: We helped the old clean their houses and chatted with them. How about you?

A: I just read a science magazine

B: Oh, really ? ?

A: Hum… it is about the main cause of smog (雾霭) and ways to beat it.

B：Great! But  ?

A: We can live a greener life by using cleaner energy to solve the problem, I think.

B: You do?

A: Yes, natural gas is a good choice. By the way， ?

B: It's 7:45 now.

A: Oh, God. Hurry up or we'll be late.

B: OK.