The Doctor discovers that the meteorite contains an alien life form.

医生发现陨石中含有一种外星生命形式。

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So I guess I shouldn’t have been surprised to find a number of definitions at urbandictionary, all very specific: an alien life form from Stargate, a kind of military vehicle from the game Halo.

所以，当我在urbandictionary.com查到许许多多对于wraith的极为具体的定义，并不该那么惊讶。 列举其中几个：《星际之门》的一种外星生物，游戏《光晕》的一种军用车辆，诸如此类。

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The borg is a character in the television show Star Trek: The Next Generation, an alien life form that is part human and part machine.

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It is not yet known if it is male or female, but names being suggested included Snowy, Frosty and Alf - related to the TV character which stands for Alien Life Form.

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It starts as a fifties war-of-the-worlds pastiche: an alien life-form arrives in a meteor and quickly mutates, threatening to destroy Arizona as we know it.

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