I promise…
这样的语句会让收信人觉得写信人是极有诚意解决这件事情的，起到了积极致歉的效果。
其他可供参考的语句有：
I am awfully/terribly sorry for what I have done.
I feel very guilty for what I have done to you.
I am afraid what I have done has caused many inconveniences to you.
Please accept my most cordial and humblest apologies for…once more.
I will try my utmost not to make such a stupid mistake again.
I am so sorry to have put you to so much trouble.
4)建议信
雅思专家分析认为，首先考生们要分清楚建议信和抱怨信有着本质的区别，前者着重在于给出一些中肯的建议，语气是可以商榷沟通的，相对比较缓和，而抱怨信的目的是为了说明问题并得到对方的回复和解决，而且这一问题常常给写信人带来生活上较大的不便。建议信的重点在于在肯定原有成绩的基础上，尽量选取较为“乐观、积极”的词语表达自己对信中所述问题的兴趣甚至是参与愿望。如：
I am delighted to learn …
In my point of view, it would be better to…
I am very interested in …
I am ready to offer the information needed.
请看下面这个例子：
You are a member of a sports club in an old building. Now all the members are asked to provide suggestions to the manager of the club about the improvement of the club building. Write a letter to offer some suggestions. In your letter, you should say:
1. Why the club is important to you?
2. What your suggestions are
3. What benefits the members can obtain after improvement.
写信人被要求向一家体育俱乐部的经理提出俱乐部设施的升级建议，一些有建设性的中肯建议再通过积极参与的态度表现出来，会更容易被接纳。
5)感谢信
在写感谢信时，分清收信人尤为重要，本是亲密的多年好友，如果用词过于客气和庄重会让人觉得矫情，对于较为陌生的收信人，如下的表达就比较合适：
I take this opportunity to express to you my deep appreciation for the kind assistance you rendered me.
I wish there were a better word than “thanks” to express my appreciation for you generous help.
My appreciation to you for your generous help is beyond words. I wish I could repay it one day.
Please accept my most cordial thanks for your timely help, which I will always remember.
Thank you from the bottom of my heart for your kind help.
6)询问信
在询问时，一些常见的客套表达是必要的：
I would like to obtain some information about…
I would like some detailed information on / about...
I am writing to you in the hope that I may obtain...
I wonder if …
另外一处体现礼貌原则的部分是在结尾对于收信人将要提供的帮助给予感谢。
I would be much obliged to you if you could let me know …
Your prompt and favorable attention to my inquiry would be highly appreciated.
I am looking forward to a favorable reply at your earliest convenience.
四、收尾落款
签名处的落款也有一定的要求，如果在称呼处用的是“Dear Mr.”等，我们习惯在此处用“Yours sincerely”，如果是称呼“Dear Sir or Madam”, 我们就会用“Yours faithfully”结尾。如果和收信人关系较为亲密，Yours, With love等甚至直接留下名字都是可以接受的。
