英语作文朋友邀请参加生日聚会因有事不能去,要表示感谢并说明原因,80词左右

Dear friend,
Thank you for your asking. I would love to, but I am really a little bit busy that day. I have to do something important. I am very sorry that I can not go to the there. I'm really sorry about that, I would like very much to join you another time. I present to you the most sincere best wishes
Happy birthday to you! I hope you have a good time.
Yours,
Mary

亲爱的朋友，
十分感谢你的邀请。我非常想去，但是我那天真的有一些忙。我不得不去做一件重要的事。我非常遗憾我不能去。我真的非常抱歉,希望我下一次能够参加。在此对你献上最美好的祝愿。
生日快乐！我希望你玩得开心。