转速

例句：

1. 1. The car's engine has a high speed, which is dangerous.
   这辆车的引擎转速很高，很危险。
2. 2. The train's speed is 80 km/h, which is fast enough.
   火车的速度是每小时80公里，已经很快了。
3. 3. The car's gearbox has a low speed, which is easy to control.
   这辆车的变速箱转速低，容易控制。