sliding gear

例句：

1. 1. The car has a sliding gear system that allows for easy shifting between gears.
   这辆车有一个滑动齿轮系统，可以轻松地在各个档位之间切换。
2. 2.The engineer designed the sliding gear to improve efficiency and reduce wear.
   工程师设计了滑动齿轮来提高效率并减少磨损。
3. 3.In the old days, people used sliding gears to power their machines.
   在过去，人们使用滑动齿轮来驱动他们的机器。