Individuals can choose these two contents: if it is the first chemistry class for junior high school students, it is recommended to do more experiments, which will easily arouse students' interest and make them more interested in learning chemistry in the future. It is best to choose those experiments with concrete or beautiful phenomena; If you are a junior high school student who has been exposed to chemistry for a period of time, you can choose those knowledge points that are easy to explain clearly, so that you are not easy to make mistakes.