number of gears

例句：

1. 1. The car has a number ofgears that can be adjusted to suitdifferent driving conditions.
   这辆车有多个档位，可以根据不同的驾驶条件进行调整。
2. 2. Themachine has a number of gears thatcan be used for various tasks.
   这台机器有多个齿轮，可以用于各种任务。
3. 3. The gears on the bicycle aredesigned to provide smooth and efficient movement.
   自行车上的齿轮设计用来提供平滑和高效的运动。