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
Dear_____,
I am writing this letter to express my apology that ______________.
I feel terribly sorry about this.
Once again, I am very sorry for any inconvenience caused. I will be really appreciated if you can accept my apologies and understand my situation.
Yours Sincerely
_________
dear mr. smith,
i am indeed very sorry that i missed the examination on international business english writing you gave last friday. i feel awful about it and want you to know what happened that day.
i suddenly fell sick early that morning and my parents had to send me to the hospital. please find enclosed a copy of the medical bill.
once again, i apologize for any inconvenience caused.
sincerely yours,
wang hua