别人发邮件邀请你参加一个活动，你当然应该回一封邮件表示感谢。
这封邮件的几种写法:
Thanks for invitation. I’ll be happy to attend.
Thank you for your kind invitation to John and Jane's engagement party on Friday, January 16 at 6:30 p.m. My wife and I will be happy to attend and eagerly look forward to helping you celebrate this happy occasion.
Thank you for inviting us to be part of Jane's graduation celebration. We're eager to see you all again. This event will make seeing you even more special.
We'll be arriving Thursday at 7:00 p.m. on flight 401. Thank you for offering to pick us up and getting us a room at the Doe Inn. You seem to think of everything.
We look forward to spending this time with you and getting better acquainted with Jane and her husband.
John and I were delighted to receive the invitation to your barbecue. We accept and are looking forward to the event. I've misplaced the invitation, but as I recall, the barbecue is on Thursday, June 15, at 6:30. Please let me know if I am mistaken. We look forward to another great evening with you.
I was pleased that you would invite me to attend Jane's retirement party. I appreciate your kind offer to pick me up at home, but I will already be in Springfield that day and plan to drive to the party myself.
I appreciate your thinking of me, and I look forward to seeing old friends again.