I'm writing to apologize for having forgotten to return the "the Beatles" CD to you when I left Canada,I was in such a hurry that I packed everything in my luggage without checking carefully.
Had I paid more attention then,I wouldn't have made such a stupid mistake.
Now something must be done to solve the problem because I understand you cherish the CD enormously.I can either send it to you by express mail or alternatively compensate you at a reasonable price.If you do not mind,I may bring it back to you next time I go to Canada.
Please let me know which solution you prefer at your earliest convenience.I really hope you will accept my sincere apology.
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.
①I am truly sorry that ______(道歉的原因).
②The reason is that ______(介绍原因).③Once again,I am sorry for any inconvenience caused.④Hope you can accept my appologies and understand my situation.