1, junior high school will choose high-quality topics, which are typical and representative, and can better help students understand and master knowledge points. The questions that must be brushed are of poor quality and not representative.

2. Junior high school training focuses on cultivating students' thinking ability. It helps students to improve their thinking ability and problem-solving ability by asking them to do difficult problems, but brushing questions can't cultivate students' thinking ability. So train well in junior high school.