A: Emphasizing the "practice" teaching method is the most basic and important proposition of Yan Yuan on teaching method after the change of academic thought. He stressed: in the teaching process, we should combine with practice and persist in practice and practice, and think that only in this way can the knowledge we have learned be really useful. So he thinks that knowledge that is not combined with his own practice is useless. "It is useless to wake up in your heart and talk on paper without learning from yourself." Based on the knowledge theory of "learning by doing" and "applying what you have learned and observing its gains and losses", he pays attention to "learning by doing" in teaching methods, which is opposite to the traditional educational methods of "sitting tight and studying behind closed doors". From the perspective of "practice", he expounded his thought of attaching importance to "practice" teaching method. He believes that the purpose of acquiring knowledge is to "implement" and "be practical" and to help people "do things in the world". Yan Yuan attaches importance to the teaching method of "practice" because he opposes the teaching method of Cheng Zhu's Neo-Confucianism, which is just words and deeds and empty talk about psychology. This teaching method is of great practical significance to oppose the teaching method of Neo-Confucianism, which is empty talk about psychology.