邀请信框架：
Dear Sir or Madam，
On behalf of sb.，I am writing this letter to cordially invite you to do sth.(give a lecture/attend an evening party).
As our distinguished guest，I am hoping that you will be available for sth.(the lecture or the party)in a specified place(地点)at a specified time(具体时间)on a specified date(日期).There will be one hour and a half(时长)for sth.(the lecture or the party)including...
Since it is a relatively formal occasion，it is also of great importance for you to pay close attention to your clothing.
I hope you will have time for sth.(the lecture or the party).I am looking forward to your reply at your earliest convenience!
Yours sincerely，
Li Ming
