The first one recommended is the chalk photo, Tang and Song Dynasties (both famous chalk teachers, all very powerful, highly recommended).

The second is the idea of Hony's public examination (the great god of mathematics Olympic Games, the lecture is very delicate, suitable for Xiaobai students to make up the foundation and push hard)

The third is Peanut Thirteen (the survey scored 86 points, with the strongest data analysis and good quantity).

I have watched the online classes of these famous teachers, and they are all in place. Of course, you can't finish it. You can choose one that suits you, which is enough.