In fact, a lecture is a general explanation and comment on a course or a class. Among them, explanation is the key. Now "explanation" is generally regarded as "lecture", which is based on teachers' oral expression, educational science theory and teaching materials, and describes the specific situation of teachers and students and the characteristics of the subject.
The problems to be clarified in the lecture are: what to teach, how to teach, why to teach like this and its theoretical basis. Comments are comments, exchanges and discussions on explanations. Teaching methods are the focus of lobbyists' attention.