Because of their narrow bandwidth, CF signals portray only the target's presence and, in the case of some bat species, its motion relative to the bat's.

因为它们的频宽很窄，CF 信号只能描绘目标的存在，而对于一些种类的蝙蝠来说，CF 信号还能描述目标相对于蝙蝠的运动。

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But the earth is in motion relative to the sun, the sun is in motion relative to some other star, and so on.

但地球相对于太阳运动，太阳相对于某些其他恒星运动，等等。

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In relativity, your observations must always be with respect to a particular observer-an observer with a well-defined motion relative to whatever is being observed.

在相对论里面，你的观察总是必须会涉及到一个特定的观察者-一个相对于被观察物有着明确的相对运动的观察者。

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Nowadays, people just jump out of the dark all of a sudden and screech (cheap scare) or creatively disembowel screeching second-string actors (more gross than actually frightening.) Couple that with a veneer of macho stylishness, and you've got yourself a relative facsimile of a motion picture.

CNN: Review: 'John Carpenter's Vampires' stinks worse than garlic

There's also a handful of elements that we seldom see in these apps, such as a direction-relative wind indicator, optional motion-driven navigation and visual themes.

ENGADGET

It requires that electricity be used to create the motion that is recaptured through regeneration from the relative weights and positions of the elevator vehicle and the counterweight.

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