There's nothing in it. It's empty. It's transparent.

里面什么也没有，它是空的，是透明的。

耶鲁公开课 - 文学理论导论课程节选

Keep in mind we do have this p orbital here and it's coming right out at us. And this p orbital is here, but it's empty, it doesn't have any electrons in it, that's why we don't have to worry about it in terms of getting our electrons as far away from each other as possible.

他们程120度角互相远离,这样它们离得最远，记住我们这里确实有个p轨道，它朝向我们，这里有个p轨道，但它是空的,里面没有电子,这就是为什么我们在考虑。

麻省理工公开课 - 化学原理课程节选