Your stomach is a very complex organ that has a muscle layer, it has an epithelial layer which is the interface with food that comes in, and it also has a nervous system, so does the heart.

你的胃是一个非常复杂的器官,它拥有一个肌肉层,有一个与摄入的食物,相接触的表皮层,也有一套神经系统,心脏也有

耶鲁公开课 - 生物医学工程探索课程节选

This should make sense to you, because they don't, in fact, want to gain another electron, because that would mean that electron would have to go into a new value of n, a new shell, and that's really going to increase the energy of the system.

这对大家来说应该容易理解，因为它们实际上不想得到另一个电子，因为这意味着这个电子不得不,到一个新的，n，值更大的壳层上去，这将会增加系统的能量。

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