来自《耶鲁大学开放课程：1600年后西方社会的流行病 第3集 第3集》

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  Rattus rattus,
  事态就发生了变化
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  the black rat or ship rat;
  屋顶鼠也被叫作黑鼠和船鼠
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  and as you see, extremely cute it is.
  也就是你们看到的这个很可爱的小东西
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  Unlike his cousin,
  和它的近亲
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  the brown rat,
  也就是家鼠不同
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  that took over its ecological niche later on,
  黑鼠一点也不畏缩
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  and is more familiar in modern times,
  后者逐渐取代了黑鼠的生态位
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  the black rat was definitely not shy,
  并且在现代更为人所知
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  but lived in close proximity to people,
  黑鼠在人类的居住地活动
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  with whom they shared the same dietary preferences.
  甚至和人类有相似的饮食习惯
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  So, the rat was extremely important.
  所以老鼠在这个传染链中是很重要的
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  The bacterium was spread in a third
  这个细菌在传染中的