The period effect was observed in the students' test scores, showing a pattern of improvement followed by decline.
在学生的测试分数中观察到了周期效应，显示出改进后的下降模式。
Educators noted the period effect in attendance rates, with higher rates in the beginning of the semester and lower rates towards the end.
教育工作者注意到出勤率的周期效应，学期开始时较高，学期末较低。