李华因在学校使用手机被学校处分，他感到很困惑，写信给你求助。请根据以下结构提示给李华回信。开头结尾已给出。所给要点必须写

A possible version:
Your letter reached me yesterday. It said in your letter that you were punished for using cellphones, which puzzled you.
There is no doubt that cellphones can bring us much convenience. We can keep in touch with friends and families wherever they are. Besides, the cellphone is a way to fun.
However, there are some problems with using cellphones. The ring of phones can disturb teachers and students in the class. It has been proved that often using cellphones does harm to health. Another problem is that some students can spend too much time and money on cellphones and sending messages, which will result in bad results in study.
As a student, he should concentrate on study. It is right for school to prevent you from using cellphones.

本文是关于手机的优缺点。要用一分为二的思想来叙述。既要肯定手机给我们带来的好处，又要指出手机的弊端。最后可以发表自己对于学生使用手机的看法。
开头可以先对问题有一个总的描述。
When it comes to ..., most people believe that ..., but other people regard ...as .... 
Some people contend that ... has proved to bring many advantages (disadvantages) 
People, who advocate that ..., have their sound reasons (grounds) 
Those who have already benefited from practicing it sing high praise of
To my point of view 。。。。。