因过失或疏忽做错了事，给别人带来了麻烦或损失，发觉后要立即写信给对方赔礼道歉，这是一种礼貌。道歉信要写得坦率，诚恳。

　　1、因未能践约赴宴致歉Unable to keep one's promise

　　Dear Miss Nancy，

　　Much to my regret I was unable to keep my promise to attend your birthday party last Saturday， owing to the fact that my little son was suddenly taken ill early that day.

　　Hoping to see you soon.

　　Truly yours，

　　Tom

　　亲爱的南希小姐：

　　小儿上周六突然生病，因此未能应约赴生日宴，殊觉抱歉，希原谅，再见。

　　2、因迟复来信致歉Because of answering one's letter late

　　Dear David：

　　I am afraid that you will think me unpardonably negligent in not having answered your letter dated 7， December sooner， but when I have told you the reason， I trust you will be convinced that the neglect was excusable. When your letter arrived， I was just in Hong Kong. As my family could not forward it to me during my absence， it has been， therefore， lying on my desk until the moment when I took it up. Now the first thing I have to hasten to do is to write to you these few lines to express my deep regret.

　　I enjoyed many pleasant sights during my trip. I shall be pleased to give you an account to of them when I see you next.

　　Sincerely yours，

　　Tom

　　亲爱的戴维：

　　请原谅我收到您12月7日的来信后迟迟未复，现将原因告诉您，相信您一定会谅解的。您的来信到来时，我正巧在香港，家人无法及时转递。你的信一直放在我写字台上，直到我回到才看见，拖至今天才回信，深表歉意。

　　这次出去旅行饱览了许多美丽景色，下次见到您时，将告诉您一切。