So even though we see a nodal plane down the center, I just want to really point out that it's only when we have a nodal plane in the internuclear or the bond axis that we're calling that a pi orbital.

虽然在中间有个节面，我想要指出的是,只有节面在核间轴,或者键轴上时,我们才叫它π轨道。

麻省理工公开课 - 化学原理课程节选

Even the characteristic thing in a polis, the agora, the marketplace,which also becomes the civic center of these towns, even these grew up later than the polis.

即使像"市",就是集市,这样城邦的标志性建筑,和城邦的中心建筑,也是在城邦建立之后才开始发端的

耶鲁公开课 - 古希腊历史简介课程节选