Yes, actually, I don't think the effect of brushing classes is that great. I think brushing classes may be simply to complete a task, and not many people will listen carefully. Once this course can be used to get credits, I think it should be more water-intensive, which not only takes up students' time, but also has no substantive effect, and students will not learn anything meaningful. However, the phenomenon of brushing classes cannot be avoided for a while, and there must be many factors.