What are your postgraduate materials? Do you mean that you want to apply for a postgraduate degree in our school? You can't buy this from the library. The school's website has the real questions of the school's professional courses over the years. For example, if you are a Chinese major, you can go to the website of the School of Liberal Arts to see the real questions. Even in some colleges, the school network sometimes has the only right to download real questions. Also, you should be a junior now, so don't worry. It is better that all your teachers and sisters in the last session have real problem sets (even real problems that have been done). You can start buying now. If it really doesn't work, wait until the school flea market opens in June, where there are almost all the real questions and bibliography you want. Come on!