1.邀请信
 Directions:
　　You are preparing to organize a lecture and in need of a prominent professor. Write a letter to invite him. Your letter should cover the following information:
　　（1） the time and place of the lecture;
　　（2） the theme of the lecture;
　　（3） the reasons of bolding such a lecture.
　　You should write about 100 words. Do not sign your own name at the end of the letter. Use "Li Ming" instead. You don't need to write the address.