来自《耶鲁大学开放课程：生物医学工程探索 第13集 第13集》

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  So, if you're going to drink water
  因此 如果喝水的话
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  you're not so worried about how big your straw is.
  就不用操心使用多大的吸管了
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  You would accept a small straw not just because
  你们更喜欢用细吸管
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  milkshakes are more delicious,
  不只是因为这能让奶昔变得更好喝
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  but because you don't need to generate as much of a pressure drop
  而是因为你不必
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  to move water as you do to move a milkshake,
  用像吸奶昔那么大的力来喝水
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  because milkshakes have a higher viscosity.
  因为奶昔的粘度很大
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  The viscosity of the blood is in general a constant,
  一般来说 血液的粘度是恒定的
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  it's a constant that is about 3 centipoise.
  大约是三厘泊
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  You can read in the book about
  你们可以看书
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  units of viscosity and how they're defined.
  上面讲了粘度单位及其定义
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  It tells you something about the force that you need
  这样我们就知道为了使液体流动