Mainly books, plus a suitable material, exams are all about the knowledge of books. When you see a question, you associate it with which knowledge point to test. It is very important to learn to summarize different types of questions, such as how to test the same knowledge point. Secondly, many exercises after class can be used as a conclusion. Many times, a question is composed of several test sites, and it will be easy to break each one. I have been there before.