Dear Prof. Smith, Many thanks for your hospitality and the knidness you showed me during my recent visit to your country. It was thoughtful of you to introduce me to so many of your famous professors and learned scholars in America. I have learned a lot from them. I returned to China dafe and sound last Friday, and have resumed my work by now. I hope to have an opportunity to pay you back for your generosity when you come to my country. Thanks again for your kindness and hospitality! Best wishes! Yours cincerely, Li Hua