There are several reasons:

1. There is no fast-forward phenomenon from the beginning to the end of the course, that is, the cumulative study time is consistent with the course duration, and if it is inconsistent, the class hours cannot be obtained.

2. Every class is signed in and appears randomly in the course. Students should be given a corresponding number of sign-ins. If the number of times is not enough, they will not get the class.

3. Complete the questions after class, and get the correct answer, that is, the test result display 100.