Lack of interactivity
Online classes can't have face-to-face conversations, and teachers can't judge whether students are paying attention by their classroom performance. Lack of mutual feedback between teachers and students.
Lack of effective management
Teachers can't directly grasp whether online students focus on the classroom and conduct timely and effective management. It is also difficult for students to maintain a high degree of concentration in class. Online classroom needs students' self-discipline.
Lack of practice
Online classroom can only impart knowledge, but can't lead students to practice in person. Practice is often the most interesting teaching content for students. Through practice, students can master what they have learned more deeply.
Combination of online and offline
But offline and offline have their own advantages and disadvantages, and the combination of the two will get better and better.