If the credit system of college students includes the elective part of large-scale open online courses, you can only get some grades after listening to all the video lessons, completing the in-class tests and final evaluation, and some courses will get more scores when you have more interaction with lecturers. However, whether it is self-study or the requirements of the school credit system, it is not recommended that you brush classes for the sake of brushing time, because only by using the knowledge in the course for me can you really learn something.