I am writing to complain about the poor service at your dining-room.

　　/ I am writing to express my dissatisfaction with / at…

　　/ I wish to make a complaint about…

　　/ I am writing to draw your attention to….

　　/ I am afraid I have got a complaint about….

　　(3) 致歉：

　　I would be grateful if you would be so kind as to provide me with certain essential information regarding the following aspects.

　　/ I am writing to you because I am unable to….

　　/ I an terribly sorry that….

　　/ I would like to express my apologies for not being able to….

　　(4) 询问：

　　I would like to obtain /request/seek/inquire about some information about…

　　/ I am writing to ask if you can do me a favor.

　　/ I would like some detailed information on/about….

　　(四)结尾段：

　　1、发出请求

　　(1)Please give this matter your immediate attention.

　　(2)I would very much appreciate it if……as soon as possible.

　　(3)Please render me some valuable advice which is conductive to my final decision.

　　2、提供帮助

　　(1)I hope these……will be helpful, and please feel free to contact me for more information.

　　(2)……will be taking responsibility for you and if you should need any assistance, she/he will be pleased to help you

　　3、 再次表示歉意或感激

　　(1)Thank you for your kind assistance.

　　(2)Please accept my heartfelt thanks and deepest gratitude, now and always.

　　(3)I am sorry that I cannot……, and trust that you will understand.

　　(4)In addition, let me apologize for any inconvenience I may have caused.

　　(5)I shall feel obliged by a reply at your earliest convenience.

　　(6)Once again, I am sorry for any inconvenience caused.