【1】
dear friends: i'm happy that you are read this letter now,it shows that you are arriving safely.
well,i want say something to you.
I ought to see you off in the airport yesterday.
unfortunately, i went to hospital with my father because of my father's sickness.
so i missed the time to say goodbye to you.
what a pity! so i wrote this letter to apologize to you.
today my father is better so i have time to write to you.
I‘m not adapting to the life without you so i holp you can back early! Your sincerely， ***
【2】
Hi Miss Liu(男的用Mr)
I am writing to express my sorry for the breaking of an appointment.
We were agreed that I will go to your office to discuss my homework on ten o'clock Monday morning, but I was busy with something else which is important for me.
I am so sorry for did not inform you about it.
Best regards
XXX
【3】
Dear Zhang,
I am really sorry to tell you that I was unable to attend your birthday party yesterday evening.
That is owing to the fact that my old friends visited my house without telling me the exact time.
I had to entertain those friends with my passion in the entire evening,and I will continue to entertain them in the following two days.
I really regret that I haven't go to celebrate your birthday personally and had missed a wonderful chance to enjoy myself with our kind colleages.
I have prepared a pretty gift to you yesterday and will send to you this afternoon to show my best birthday wishes.
Besides, I trust that you will understand me.
Best wishes,
yours sincerely,
Tom