X-gear pair

例句：

1. 1. The X-gear pair on the car is designed to improve fuel efficiency.
   汽车上的X型齿轮对设计用来提高燃油效率。
2. 2. The X-gear pair in the gearbox helps to reduce friction and increase speed.
   变速箱中的X型齿轮对有助于减少摩擦并提高速度。
3. 3. In this new design, the X-gear pair has been optimized for better handling and control.
   在这个新设计中，X型齿轮对已经被优化以获得更好的操控和控制。