Because there are not some versions of textbooks on this platform, and because teachers are different, it is impossible to have all versions of textbooks.

At present, the national platform can study the whole semester's courses, and the teachers inside are basically famous teachers such as Xicheng and Haidian, and they feel really good. Many teachers in the municipal platform are school teachers and have never heard of them. However, the online courses on the national platform also have shortcomings, that is, the class hours are too short, and sometimes the feeling is not thorough enough.