1、投诉信
　　投诉信的开头常用句式和套话
　　I am writing to inform you that I am dissatisfied with your …
　　投诉信的结尾常用句式和套话
　　I understand you will give immediate attention to this matter.
　　I would like to have this matter settled by the end of …
　　2、询问信
　　询问信的开头常用句式和套话
　　I would be most grateful if you could send me information regarding/concerning …
　　I am writing to see if it is possible for you to provide me with information regarding …
　　询问信的结尾常用句式和套话
　　Your prompt attention to this letter would be highly appreciated.
　　I am looking forward to hearing from you.
　　3、请求信
　　请求信的开头常用句式和套话
　　I am writing to seek for your assistance in …
　　请求信的结尾常用句式和套话
　　I would like to thank you for your generous help in this matter.
　　4、道歉信
　　道歉信的开头常用句式和套话
　　I am writing to apologize for …
　　I am writing to say sorry for …
　　道歉信的结尾常用句式和套话
　　I sincerely hope that you will be able to think in my position and accept my apologies.
　　5、感谢信
　　感谢信的开头常用句式和套话
　　I would like to convey in this letter my heartfelt thanks to you for …
　　感谢信的结尾常用句式和套话
　　I must thank you again for your generous help.
　　6、建议信
　　建议信的开头常用句式和套话
　　I am writing to express my views concerning …
　　You have asked me for my advice with regard to … and I will try to make some conducive suggestions.
　　表达建议常用句式和套话
　　I feel that it would be beneficial if …
　　I would like to suggest that …
　　I would recommend that …
　　If I were you，I would …
　　You may consider doing …
　　It would seem to me that you could …
　　As you may agree that …
　　建议信的结尾常用句式和套话
　　I would be ready to discuss this matter to further details.