gear-box

例句：

1. 1. The car's engine needs to be tuned for optimal performance.
   汽车的引擎需要调校以获得最佳性能。
2. 2. The mechanic replaced the worn gearbox with a new one.
   机械师用一个新的替换了磨损的齿轮箱。
3. 3.The engineer used a gearbox to increase the vehicle's efficiency.
   工程师使用一个齿轮箱来提高车辆的效率。