What about the Russian graduate students in Xiamen University? What should I do to prepare for them?

Russian is really a very complicated language. Even if you learn it well in China, it is no worse than those who have stayed abroad. Because even if you know grammar and syntax, you can understand it, which is still wrong, so it needs a lot of practice and efforts. Moreover, now that Russia's economy is declining and the ruble is depreciating, you should consider the opportunity to study well in China and then apply for free public schools. Come on, you must be patient when you choose this language. It's totally different from English.