driving speed

• 掘进速度

driving speed的用法和样例：

例句

1. A gearing mechanism of a motor vehicle engine that reduces the power output required to maintain driving speed in a specific range by lowering the gear ratio.
   (汽车的)超速档机动车辆的一种齿轮装置，通过降低齿轮比率来减少为将车速保持在一定范围内而需要的输出力