假如你叫李丽，下面是你和Sam的对话，请你根据对话内容写一篇60左右的英语短文(开头部分不计入)，给寄宿在你家的外国朋友Jack介绍一下Sam。

Li Li: Hello. I'm Li Li. What's your name?

Sam: I'm Sam. Sam Green. I'm from the UK.

Li Li: I'm 13. How old are you?

Sam: We are the same age. Can you tell me what our first class is?

Li Li: Sure. It's math.

Sam: Oh, I like it. Math is my favorite subject. It'sa little(有点) difficult but interesting.

Li Li: Really? Math is too difficult for me. I like P.E.

Sam: I like P.E., too. Tennis is my favorite sport.

Li Li: The second class is P.E. We can playtogether(一起).

Sam: Great!

    Hello, Jack. I have a new classmate.