求英语作文,要求如下: 假如你是李明,你收到一封你的美国朋友Peter的邀请信.他邀请你去参加他周六的生日聚但是你不能参加.请写一封回信告诉他,你不能接受他的邀请的原因并致歉.词数80左右,要点提醒:1.感谢对方的邀请,并对你不能参加他的生日聚会表示遗憾.2.阐述你不能去的原因3.致歉并祝福

I can not go to birthday party
I can not go to your party, and I'm really sorry, I do not for a reason, one of my family is sick, thank you for your invitation, I am sure you will forgive me, right?
We are good friends, you will not because it does not bother me now! I know you do not, you will not!
Thank you again, next time I will not miss!
Happy birthday to you, good health and pass exams!
我不能去生日聚会
我不能去你的聚会了，实在对不起，我不去是有原因的，我的一位家人生病了，感谢你的邀请，我相信你会原谅我的，对吧？
我们是好朋友，你不会因为这样就不理会我了吧！我知道你不会，你一定不会!
再次感谢你，下次我绝不缺席！
祝你生日快乐，身体健康，考好成绩！

Dear Peter:
Hi!i am Liming.I am very happy when i received your invitation,but i have to tell you that i can not go to your party because Saturday is my grandma`s birthday too,i had promised my grandma i will go to her house and held a party for her.So,i am sorry,i can not go to your birthday party,and thanks for your invitation.Don`t worry,i will send you a gift on saturday,and i will miss you every day and every night.
Yours sincerely
Liming