but you can sort of tell that the particle is moving slowly or rapidly by looking at the space in between these tick marks.

但你可以通过观察计时点之间的距离,来判断该物体运动的快慢

耶鲁公开课 - 基础物理课程节选

A clock tells you what time it is, but you can also say what time it is by seeing how fast the particle is moving because you know it started with some speed.

时钟能告诉你现在的时间,但你也可以通过测量质点速度,来判断当前的时间,因为你知道它的初速度

耶鲁公开课 - 基础物理课程节选