It's the most simple-- or often called a bill-- a discount bond does not pay interest; it's sold at a discount.

它是最简单的,经常被称为国库券,它是一种贴现债券,且不付息,并以折扣价发行

耶鲁公开课 - 金融市场课程节选

All right, so that's really all there is to thinking about valence bond theory in terms of the most simple explanation here.

好了，这就是,价电子轨道理论的,最简单的解释。

麻省理工公开课 - 化学原理课程节选

So, using our simple valence bond theory, what we would expect is that we want to pair up any unpaired electrons in methane with unpaired electrons from hydrogen and form bonds.

利用简单的价电子成键理论，我们预计,要把所有甲烷中没有配对的电子,和氢原子中没有配对的电子配对来形成键。

麻省理工公开课 - 化学原理课程节选