参考答案：
1. 翻译
It is easy to change rivers and mountains but hard to change a person's nature.
全文：
Conversation B
(Pete walks into Nate’s Place.)
Cindy: Pete! I put my change into this Can for Catalina. You’ll have a fun trip!
Nate: That’s so kind of you, Cindy.
Pete: Thanks, Cindy!
Cindy: Pete, is our graduation today?
Pete: No.
Cindy: Why are you wearing your cap and gown?
Conversation C
Pete: All of the seniors are wearing their cap and gown today. We’re collecting the money in the cans. And we’re encouraging people to donate more.
Cindy: Well, I don’t have any more to donate. I’m sorry.
Nate: Here, Cindy.(gives her $20) Give Pete $20. You can pay me back later.
Cinay: (gives money to Pete) Here,Pete. Enjoy the trip.
Pete: Thanks,Cindy! If I can do anything for you, please tell me.
Key words
graduation (n) 毕业典礼；毕业
The graduation is fun! I liked your speech.
pay [someone] back (v) （对某人）偿还
Do you need some money? You can pay me back later.
cap (n) （毕业时戴的）方帽
gown (n) （毕业时穿的）礼袍