"Good at recovering losses" comes from "those who are good at recovering losses" in Xue Ji, which requires teachers to give full play to the advantages of students and overcome their shortcomings as much as possible. "Xue Ji" said: "Scholars have four mistakes: if they lose more, they will lose less, if they lose more, they will be easy, and if they lose more, they will stop." It means that some people are greedy because they are well informed; Some people have learned too little because they attach importance to keeping their promises; Some people have the courage to make progress and take learning too lightly; Others are not confident, too cautious and easily afraid of difficulties. In view of the students' situation, teachers should suit the right medicine, foster strengths and avoid weaknesses, that is, adhere to the principle of "saving the lost".