If a appears to be moving at a steady speed relative to b.

如果A看上去以相对于B稳定的速度运动。

youdao

You should travel at a safe speed relative to the motion of the other vehicles on the road.

你应该使用一个对于道路上其他车辆相对安全的速度行驶。

youdao

Like racing cars that swerve and hit each other on a circular track, the moons' speed relative to each other is low because they travel in nearly the same orbit.

这有点像是突然转向的赛车在环形赛道上相撞，月亮们也在同一轨道公转，所以他们之间的相对速度很小。

youdao

Other passengers say it's a reliable and comfortable service but those with experience of European trains say the American ones are a pale reflection - in terms of frequency, speed and relative luxury.

BBC: Could the US crack high-speed rail?

In hedge funds, he sees a growing interest in relative speed.

FORBES: Firms Look to Event Driven Trading for Greater Alpha

Some attribute the drug's popularity to the relative speed with which it is flushed through the body, allowing employees to pass drug tests when they return to work from leave.

BBC: Canada boomtown under pressure