参考答案：

Dear Mr. Smith,

I'm so excited to know that our school is organizing an activity to help the kids in a school. I hope I can join in it. I think I have the abilities to help them. First，I'll get on well with the kids there. I can do it because I always communicate well with others.

And I have a few hobbies, such as playing basketball, ping-pang and singing songs, so I'm going to help organize after-class activities. Also, my English is good. I can help the kids with their pronunciation. I'll read English aloud with them and teach them English songs, It's really fun.

I'll be thankful if you give me the chance!

Yours.
Yang Pei