1. Preview is the process of becoming familiar with new knowledge. It mainly depends on where the knowledge points will be tomorrow. To put it simply: focus on the key points.

2. Attending class is a supplement to the preview. Focus on learning the key content and learn and master it.

3. Homework is to master and practice the key knowledge points in class, to consolidate and test your mastery.

4. Review is to sort out all the recent key points and focus on reviewing the forgotten key points.