periodometer

例句：

1. 1. This periodometer can measure the length of a cycle accurately.
   这个周期计时器可以准确地测量周期的长度。
2. 2.The teacher used a periodometer to demonstrate how the earth orbits around the sun.
   老师使用了一个周期计时器来演示地球是如何围绕太阳运行的。
3. 3. He set up his periodometer to record the daily temperature fluctuations in the city.
   他设置了他的周期计时器来记录城市每天的温度波动。