答案：
One possible version：
Dear Tom,
Thank you very much for your kind help when I stayed in America . With your help , my English has improved a lot and my teachers and friends are surprised at my fluent English.
How is Mr. Smith ? I want to know something about his life. I tried to get in touch with him ,but unfortunately I don’t have his address and can’t connect with him .Do you have his email address or his telephone number?
The spring festival is coming . It is an important traditional festival for Chinese , when all the family members get together. It is like Christmas in the western countries .Would you like to come to feel the Chinese culture ? I am sure you will live happily here and learn a lot of funny things . Besides, I can also show you around some places of interest.
Best wishes ! I am looking forward to your reply .
Yours ,Li hua
题目分析：根据要求可知本文是一篇书信体裁的书面表达。要点有1）.感谢Tom对你学习上的帮助 ；2）询问Mr. Smith的近况并索要其联系方式；3） 邀请Tom在春节期间来中国感受中国文化等三方面内容。建议可以采用三段式的结构安排。根据内容可以判断本文可以使用一般现在时和第一人称。在写作时还要注意书信的格式。此外，为了文章的语言顺畅，要使用适当的连接词。要尽量使用熟悉的词汇和短语，避免语言性错误，但同时要采用多种句式以提高文章的档次。
【亮点说明】本篇范文要点全面，思路清晰，层次分明，语言自然流畅，而且使用了一般现在时和第一人称，很好地完成了写作任务。作者用三个段落分别表述了三个要点的内容，开始先表达了自己的感激之情；然后询问史密斯先生的情况；最后提出邀请。在写作时作者较多地使用了简单句，使书信语言亲切自然，定语从句when all the family members get together.和短语With your help以及连接词Besides的使用有效地起到点缀的作用，避免了语言的单调。