Preview before class, have your own understanding of the exercises, follow the teacher's ideas in class, and then compare the teacher's ideas with your own, independent of the teacher's ideas, you can find new ideas on this basis, but you should take notes carefully for the questions that you can't find ideas, and think about them after class. You don't need to do many questions, you should be precise and detailed, and your ideas should be clear. Learn from other people's ideas first, and then establish your own thinking mode.