Reading textbooks is the most primitive and simple. Don't just read books. Thinking about the invisibility of knowledge points when reading. You can ask questions appropriately and solve them yourself. You don't know how to ask your classmates. Start with the basics. You should practice math with books and understand the problems you have done, or don't do them. It's a waste of time. Don't remember too much about chemistry. Listen in class and write it down if you don't understand. What I said in the past must have been the difficulties of being compressed, but if I do it myself, I can't grasp the priorities. Besides, it is a good textbook to fully explain this book, which was written by Wang Houxiong. You can have a look. It is very detailed.