If you take the mechanical test, you will take politics, English, mathematics and specialized courses. There are several specialized courses, you can choose one, generally theoretical mechanics, control engineering foundation, technology and so on. Just go to the website of the graduate school of the university you want to apply for. Every year, every major and direction will have very detailed examination subjects and designated teaching materials. It doesn't change much every year, just look at last year's.

Ps: Huake's machinery is very good, and the estimated score is quite high. Get ready.