假设你是Peter，你的同学Mike经常在教室里随地丢纸片、塑料袋等；他还避开父母和老师抽烟。作为同学， 你将如何劝说他改掉不良的习惯？请你给他写一封信。
要求:1. 用上所有提示，可适当发挥；      2. 语言正确，行文流畅，书写规范；
3．词数：80左右。信的开头和结尾已给出；4．文中不能出现真实姓名及校名。
Dear Mike,
As your classmates and one of your best friends,                                      
                                                                              
                                                                              
                                                                              
                                                                              
Yours,
Peter