Two opposing scenarios, the "arboreal" hypothesis and the "cursorial" hypothesis, have traditionally been put forward concerning the origins of bird flight.

关于鸟类飞行的起源，传统上提出了两种对立的假设：“地栖说”和“树栖说”。

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Like bird flight, you know human thought to be possible.

和鸟类飞行一样，你知道人类思维是可能的。

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Airplanes do something clumsy, useful and only slightly similar to bird flight.

飞机可以笨拙飞行，很有用，但和鸟类飞行相似仅有一点点。

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Obie spread his arms like a gaunt bird ready to take flight.

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Libes has formed a new accelerator for mission-driven companies in Seattle called Fledge (as in fledgling bird about to take flight).

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Or in-flight flight, which grants its bearer the ability to fly like a bird, but only within the confines of an airplane.

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