Dear Henry,

　　Happy birthday to you

　　I got the invitation to your birthday party yesterday morning.(我昨天早上收到了參加你的生日宴會的邀請)Thank you for inviting me to join in your party. (謝謝你邀請我參加你的生日宴會)I tried to reschedule my activities, but I‘m sorry to tell you that I’ll not be able to join you.(我努力地重新安排我的行程表，但是很抱歉我不能參加你的生日宴會)My boss and I have to leave for shanghai next week for an international trade affair.(我和我的老板下周要去上海處理國際貿(mào)易方面的事霧)There is not any possibility of cancelling it(不可能取消)I will go to see you as soon as I am back.(我一回去就去看你)I am sure you will have a great fun at the party.(我相信你的生日宴會一定充滿了樂趣)

　　Sincerely yours

　　Jane