(1) Go to the Postgraduate Entrance Examination Forum. There are the largest number of people there, all of whom were tested. There is a special section where most of my research friends met at that time. There are a lot of materials, all of which are downloaded for free.

(2) Taobao. There are still a lot of postgraduate entrance examination materials on Taobao, so it's no problem for you to search them yourself.

(3) drinking water BBS. It's the BBS of Jiaotong University, where the news is very internal, but it's difficult to register because you need any school email.

In short, after these three lines come down, you can basically gain something.