timing-gear case

例句：

1. 1. The timing gear is crucial for the operation of the machine.
   定时齿轮对于机器的运行至关重要。
2. 2. The timing gear is responsible for adjusting the speed of the motor.
   定时齿轮负责调整电机的速度。
3. 3.The timing gear is used to ensure that the machine operates at the correct time.
   定时齿轮用于确保机器在正确的时间运行。