permanent grade

例句：

1. 1. The school has a permanent grade system for students.
   学校对学生有一套永久的等级制度。
2. 2. He has been in the same permanent grade since he was in elementary school.
   他从小学开始就一直在同一个永久年级。
3. 3. The teacher explained that the permanent grades would determine which students could advance to the next level.
   老师解释说，永久等级将决定哪些学生可以晋级到下一个级别。