来自《耶鲁大学开放课程：环境政治与法律 第1集 第1集》

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  you can taste it,
  你可以尝一尝
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  you can feel it burning in the back of your throat.
  你会感觉到你喉咙的后面在燃烧
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  So most people understand
  因此多数人都理解
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  when they are exposed to diesel exhaust.
  当他们暴露于柴油废气中的时候
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  Well, one of the interesting intents of the EPA
  环境保护署的一个有趣的意图
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  was to reduce the particle size, to reduce the larger particles.
  是减小颗粒的尺寸 缩小较大的颗粒
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  And what happened when the engines became more efficient
  接下来发生了什么 当引擎变得更有效
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  to accomplish that was they produced more,
  实现了产生更多
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  but smaller particles.
  但更小的颗粒
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  So the finer particles, less than one micron in size,
  这些微小的颗粒 在尺寸上小于1微米
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  not thinking that these finer particles can be more deeply inhaled
  并没有想到这些更微小的颗粒
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  into the lung, they reside there,
  会被吸入更深进入肺部 它们就留在那