Set a goal for yourself, brush the questions bored, and you will feel bored. But when you set yourself a goal, for example, if you do a set of questions and set yourself a goal, you can't make more than two mistakes in 20 multiple-choice questions. Then when you reach this goal, you will feel that your behavior seems meaningful, especially when you brush the problem to the bottleneck, that is to say, you have done a lot of post-mention, but not much. Find out the reasons and goals, and then you can go into battle lightly, improve your learning efficiency and improve your academic performance.