One possible version:

I am writing to ask whether you are able to do me a favor, ties, and with interests similar to mine. In my mind, she is someone who is interested in travelling, swimming, and playing table tennis. Besides, it would be better for her to have a pet dog as I have kept one at home for some time. With such a pen friend, I hope I can share with her our experiences in travelling, taking care of pets, or whatever we have in common. And I believe I will improve my English by doing so and learn more about her country.

I look forward to hearing from you soon.

Best regards,

Li Hua

题目分析：考查半开放性作文。本文主要是描述笔友的条件，可以用你身边的一个人的情况作文对照，进行详细描述。。需要注意紧扣文章主题，给出的要点都需要包括，缺一不可。写作时注意准确运用时态，上下文意思连贯，符合逻辑关系，不能出现文章脱节问题。尽量使用自己熟悉的单词句式，同时也要注意使用高级词汇和高级句型使文章显得更有档次。同时注意要求的字数，不要太多也不要太少。

点评：半开放性作文给出了一个话题，并有部分的文字提示。给考生自由发挥的余地较大。对于考生的综合能力要求较高，要求考生有很强的谋篇布局的能力和组织要点的能力。在完成开放性作文时，首先要选择自己熟悉的短语或者句型，在你的能力范围之内，选择句式时要赋予变化，因为这样你才可以更好的驾驭。同时也要选择合适的连接词，把各个要点组织成一个完整的整体，如besides, further, last but not least等。在发表个人观点的时候，可以使用谚语来提升整个文章的档次和文采，也能增加得高分的可能性。