Reviewing the knowledge that you can't remember can not only strengthen your memory, but also gradually develop the habit of positive thinking. 3. Point method: seek the main points of knowledge points in the review process, and grasp the main points to grasp the trunk of the problem. Comparative method: find out the characteristics and similarities of knowledge in various subjects, and strengthen the review effect by seeking differences in similarities or seeking common ground in differences. Summary method: find out the internal relationship of all kinds of knowledge, and then concentrate the knowledge to remember.