I could hear the beat of its propeller, churning the waves with steady speed.

我听到它的推动器快速有规律地拍打着水波的声音。

It starts at zero and eventually the galaxies are moving apart at a steady speed.

它从零开始，最终星系以稳定的速度分开。

Just travel at a steady speed a safe distance from the car ahead of you and avoid braking unless necessary.

只需以稳定的速度行驶，与您前面的汽车保持安全距离，除非必要，否则避免刹车。