【正确答案】One possible version：
Huanghai University 　 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 March 10，2010
Dear John：
　 How are things ? I am writing to you because 1 was told that you’ve spent much of your time playing computer games．I do hope that you'll give it up．
　 In my opinion, playing computer games will waste a lot of your time，and it will affect your study． Besides，playing computer games for a long time will also do harm to your health．I hope you will pay some attention to my suggestion，and stop playing computer games．
　 Thank you for taking time to consider my suggestions． 　 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 Yours Sincerely，
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 Li Ming