In the first stage of review, we should read the teaching materials comprehensively, check for leaks and fill gaps, and completely remove the obstacles to understanding in the knowledge structure. Because the knowledge that students have mastered in the past study is often fragmentary and unsystematic, comprehensive reading of history textbooks is helpful to master the knowledge as a whole, and also helps to find some previously neglected links or dead ends. In addition, what you know may not be deeply understood. Let students read through with questions, which is helpful to understand the content of the textbook in depth.