i am sorry written you a letter at the times 填什么

-I am sorry i forget （ ） the letter for you --I am sorry Iforget to post the letter for you. I'm sorry I am very busy at the a______.I'll call you back a A:I am sorry,I ------------at you the other day B:Forget it ——I am sorry.I forgot to post the letter for you. I am sorry that I （）（forget）to post the letter for you 动词填空. I am sorry to trouble you._____ where can I post my letter?A Have you ever written a letter to the Santa Claus? 英语翻译hi!I am sorry that i haven't written to you in so long,s I am sorry I can not go .I will call you ___________填什么some Sorry I can not come to the phone,I am a bit tied up at the I have already written the letter.改为一般疑问句.written改为什么形式?