gear pair with reference centre distance

例句：

1. 1. The car's engine is connected to the gearbox with a belt.
   汽车的引擎通过皮带与齿轮箱相连。
2. 2. The old man adjusted the gears on his bicycle for better speed.
   老人调整了他的自行车上的齿轮，以获得更好的速度。
3. 3. The train was slowed down by the gears in the locomotive.
   火车被机车上的齿轮减速了。