Dear Xiao Ling,
I’m very glad to receive your letter today. How are you getting along with your study?
I am pleased that you want my advice on whether you should buy a mobile phone or not. If you do not mind, I suggest that you should not buy one. Why? First, it takes up too much time to send or receive short messages. Therefore the time that you should spend on studies becomes shorter. Second, it is forbidden to use mobile phones at school because sometimes you have to respond the call in class. Otherwise, your behavior can disturb others. Third, you may be disturbed by some false short messages. Furthermore, as a student, you have to ask parents for the phone expense. That is, they will burden more to support you than before.
You must, of course, use your own judgment, but I would suggest this.
Best wishes.
Yours,
Li Lei.
这题是要点作文，写作时，要将要点写全，还不能逐字逐句翻译，切记不能用汉语的表达方式，要用英语常用短语和句型，如范文里的 I am pleased that you want my advice on whether you should buy a mobile phone or not.这句话中出现了两个宾语从句，the time that you should spend on studies becomes shorter.这是定语从句，it is forbidden to use mobile phones at school because sometimes you have to respond the call in class.这是it做形式主语的用法，当然，写作时不能忽略文章的连贯问题，可以用First 、Second、Third,连接，还要根据文章的句子间的逻辑关系选用适当的副词，如：Therefore 、Otherwise等。