三速链轮

例句：

1. 1. The car has a three-speed gearbox for easy driving.
   这辆车有一个三速变速箱，便于驾驶。
2. 2. The machine uses a three-speed transmission to increase efficiency.
   这台机器使用三速传动来提高效率。
3. 3. The engineer designed the three-speed gearbox to suit the needs of the construction site.
   工程师设计了三速变速箱，以满足建筑工地的需求。