graded time step

例句：

1. 1.The students were given different grades basedon their performance.
   学生们根据表现被给予了不同的等级。
2. 2. The company has a gradedsystem for its employees.
   公司对员工有一个分级制度。
3. 3. The graded results are displayedon the board.
   分级结果在黑板上显示。