来自《耶鲁大学开放课程：生物医学工程探索 第2集 第2集》

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  so now you have thin region of fat
  所以现在就得到了
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  which is surrounded on both sides by water.
  两侧均被水包围的薄层脂肪区域
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  This is a really interesting system
  这真的是一个有意思的系统
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  because it also solves a problem for the cell.
  因为它也解决了细胞面对的难题
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  The problem it solves for the cell is
  它为细胞解决的问题是
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  how to do I make a barrier around myself to
  当我体外和体内大部分都是水情况下
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  define what's in me and what's outside of me
  我怎样在自己周围设置一个界线
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  when most of what's around me and what's in me is water.
  来区分什么是体内的 什么是体外的
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  So inside the cell mostly water,
  那么细胞内大多是水
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  outside the cell mostly water,
  细胞外大多也是水
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  but I need to separate my water from the water outside.
  但我需要将体内的和体外的水隔离开
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  We'll see why they have to separate that in a minute,
  我们马上会讲到为什么要把它们隔离开