The third stage, that is, withdrawing from the by-election, is the stage after the lottery failed in the primary stage. At this stage, students can choose compulsory courses according to their own needs and within the range of balanced number of students in each course. In the Interim Measures for the Administration of Course Selection of Fuzhou University, it is also clearly pointed out that the credits of the courses taken in each semester are generally no more than 25 credits and no less than 15 credits.