rotations

柯林斯词典

1. N-VAR Rotation is circular movement. A rotation is the movement of something through one complete circle. 旋转; 转动
...the daily rotation of the earth upon its axis. …地球围绕地轴的每日自转。
2. N-UNCOUNT The rotation of a group of things or people is the fact of them taking turns to do a particular job or serve a particular purpose. If people do something in rotation, they take turns to do it. 轮流
He grew a different crop on the same field five years in a row, what researchers call crop rotation. 他连续5年在同一块地上轮流种植不同作物，研究人员称之为轮作。