1. Members need to be changed, because every year, members of the student union should be updated, promoted and inactive members eliminated, so as to ensure that all students in the student union are active members.

2. Every year, there will be seniors who need to practice, find jobs or study, so some seniors will retire and then someone will be needed to take their place, so it is necessary to change jobs.

Every year, there will be new students in the school, and there must be talents among them. Since talents will be absorbed into the student union, it is necessary to recruit new students.