I think it's really brave of you to go to China to study medicine. I have studied in several countries (Russia, Poland, Scotland, Holland) and although I couldn't speak Russian at first I learned it quickly enough. I went to poland to study veterinary medicine last year, but despite the previous experiences in Russia it was very different because the teachers were not speaking their motherlanguage (as they did in Russia) so they couldn't really explain what they were meant in English and half of the power points were also in Polish, so eventually I decided not to go back and finish my degree there. I really hope for you it will be different, although I don't have very good experiences with Chinese speaking perfectly understandable English. On google books you can already read up on your basic human anatomy and I would surely recommend you to familiarise yourself with some basic Mandarin and biochem, diseases, etc. Good luck!