So what that means is that we're limited in any atom to having two electrons per orbital, right, because for any orbital we can either have a spin up electron, a spin down electron, or both.

这意味着在一个原子内,每个轨道上可以有两个电子，对吧，因为对任何轨道,我们可以有自旋向上或者自选向下或者两者都有。

麻省理工公开课 - 化学原理课程节选

We're already using it up in this pi bond here, so that means we're limited to only two other spots on the molecule, so we have three.

我们已经把它用到这个π键里去了，所以这意味着,我们在分子里只剩下两个位置，所以一共是三个。

麻省理工公开课 - 化学原理课程节选

So, our detection devices are a little bit limited here today, we're actually only going to be using our eyes, so that means that we need to stick with the visible range of the electromagnetic spectrum.

我们今天所有的探测仪器十分有限，实际上我们要用我们的眼睛来观测，这意味着我们只能看到,电磁谱中的可见光区间。

麻省理工公开课 - 化学原理课程节选