grading function

例句：

1. 1. The students are graded on their performance in the exams.
   学生们根据他们在考试中的表现被评分。
2. 2. The teacher gradings the work of her students.
   老师对学生的作品进行评分。
3. 3. The company has a system for grading its employees based on performance.
   该公司有一个基于表现的评级系统。