来自《耶鲁大学开放课程：新生有机化学 第2集 第2集》

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  Now when I say 'unusual',
  我这样讲
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  that implies that you know what usual stability is.
  是假定你们知道何为寻常稳定性
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  So compared to what is it unusual?
  它有什么不寻常呢
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  And we'll address that question later on.
  这个问题我们以后会讲
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  So let me just give you finally an example of equilibrium versus resonance.
  我最后再举例对比一下平衡与共振
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  So this, as you'll learn when you learn functional groups,
  你们学到官能团的时候
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  is a carboxylic acid, and you could have the hydrogen attached
  就会认识羧酸
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  to this oxygen or it could be attached to the other oxygen.
  这里的H可以连在任何一个O上面
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  So these are not just the same thing upside down.
  这并不等于把分子翻了一转
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  It's the hydrogen being attached to one
  而是H被连到任意一个O上
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  or being attached to the other of the two oxygens.
  而这两个O是不同的
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  And, in fact, it is that way.
  事实上也是如此