Knowledge, like the world in which it is produced, is complex in itself, but what should be presented to the learner is something simple and pure. It has been more than a year since I stepped into the Internet education industry. From the one-on-one live K12 class to the video + APP practice class of the postgraduate entrance examination, to the memorization of words in the tool direction, I started to slow down on the question of "what is the essence of education". Learn slowly. "Shuowen Jiezi" says: "Teachers, what the top gives and what goes down; educating, adopting sons and making them do good." This sentence emphasizes the function and role of educators as the subject of education: educators themselves need to have good character, pay equal attention to words and deeds, and teach the educated. The interpretation of "Shuowen" emphasizes morality. Even if this sentence has passed a thousand years, it still holds true in contemporary times. But from the perspective of knowledge granting and acquisition, the learner and knowledge are the protagonists in sms marketing service this process. What is the essence of education? From the perspective of knowledge learning, I think it is to improve the degree of matching between learners and knowledge. How to improve the matching degree?