One possible version:

Dear Tom,

      I am now back China and sound. In this letter I would like to convey my heartfelt appreciation to you for

your kind assistance in my English learning when I was in New York. Additionally, your generous help and

tender care made me feel warmly welcomed and transformed my first American trip into a unforgettable

memory.

     I have been missing our English professor, Mr. Smith whose unusual cast of mind, wide and varied

knowledge, together with a singular personal charm, combined to exert a strong influence on me. What about

him recently? I desire to contact him for some suggestions on improving my listening ability. However, his

email address is not available. So would you mind delivering it to me via the online mailbox?

      I am more than delighted to invite you to join us to celebrate the Spring Festival -Chinese Lunar New Year

so that I can repay your friendship. You can partner with me to have a try in lion dances ,which is extremely

exciting. And the grand lantern festival parade will be bound to impress you. I assure you that you would enjoy

visiting here as I did at you home.

     With my best regards!                          

                                                                                                                        Yours cordially,

                                                                                                                               Li Hua