cyclic variable

例句：

1. 1. In the model, the cyclicvariable is used to represent the time-varying nature of the system.
   在模型中，循环变量用于表示系统的时变特性。
2. 2. The cyclic variable is a keycomponent in the design of the control system.
   循环变量是控制系统设计的关键组成部分。
3. 3. The cyclic variable can be used to model thebehavior of a system over time.
   循环变量可以用来模拟系统随时间的行为。