来自《耶鲁大学开放课程：金融理论 第4集 第4集》

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  You're right.
  你是对的
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  You're right, but finance is different.
  你是对的 但金融是不同的
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  We don't have to worry about those problems supposedly."
  我们无需担心这些问题
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  So go ahead back there, you.
  那么请继续你的问题
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  Student: Externalities.
  外部效应
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  So one critical shortcoming of this argument is
  这个论点的一个重大缺陷就是
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  that there are externalities.
  存在外部效应
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  Suppose that X is cigarettes,
  假设X是香烟
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  and A buying and smoking more cigarettes makes B sick.
  A购买烟草并吸烟导致B生病
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  So that's not part of this.
  但这不是论证中的一部分
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  Why is that not part of this?
  为何不是
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  Because B's utility depends only on what B's consuming,
  因为B的效用取决于B的消费