It's good. An interesting phenomenon of "27 1" in the class: in each class, the students' performance is roughly as follows: 20% children have excellent grades and are active in learning; 70% of the students' performance is average; In addition, 10% of children are students with learning difficulties. Among them, 70% of the students with medium grades show two directional development trends, one is to strive to develop upwards towards 20%, and the other is to slowly slide below 10%. The goal of education should be to promote 10% children to improve their learning efficiency, and to maximize 70% students to flock to the ranks of top students.