来自《耶鲁大学开放课程：基础物理 第1集 第1集》

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  An object falls off a tall building.
  一个物体从一栋高楼上落下
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  The object could be a person.
  这个物体可能是个人
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  So we don't ask why is this guy ending it all today?
  我们不去追究他今天为什么要自杀
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  We don't know, and we cannot deal with that.
  我们不知道 也解决不了
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  So we don't answer everything.
  我们不是什么事情都管
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  We just want to know when he's going to hit the pavement,
  我们只关心他什么时候摔到人行道上
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  and with what speed.
  以及他落地时的速度
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  So we ask very limited questions,
  我们研究的问题是非常有限的
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  which is why we brag about
  正因如此我们才敢自豪地说
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  how accurately we can predict the future.
  我们能非常精确地预测未来
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  So, we only ask limited goals
  我们的目标很简单
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  and we are really successful in satisfying them.
  而且我们能很轻松地达到目标