来自《耶鲁大学开放课程：基础物理 第9集 第9集》

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  If you want to get your money's worth,
  如果你想"力"有所值
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  you've got to take the doorknob
  你必须把门把手
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  as far as you can and put it near the end.
  放在尽可能远的另一端
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  Okay, then, you figure that out.
  好了 于是你想明白了
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  Then you come along and you say,
  于是你过来说道
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  "Okay, I've put the doorknob at the right place,
  "好了 我已经把门把手装到了正确位置
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  open the door,"
  开门吧"
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  then you're applying enormous force this way.
  于是你朝这个方向花了九牛二虎之力
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  And again frustrated,
  又一次无功而返
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  again you're getting no results,
  又一次毫无建树
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  you say, "I'm going as far as I can from the hinge,"
  你说 "我已经移到了离铰链最远的地方"
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  and it dawns on you that
  你开始明白