So, in contrast, if it has a low electronegativity, this then is going to be an electron donor.

那么，相反地，如果它的电负性很低，它将会是一个电子的施主。

麻省理工公开课 - 化学原理课程节选

So the minus vector is the same vector flipped over, pointing the opposite way.

因此负矢量即为同一矢量的翻转,指向相反的方向

耶鲁公开课 - 基础物理课程节选

sa So we have 1 s a, and we're drawing this as having a positive amplitude, but since we have destructive interference we're going to draw 1 s b as having the opposite sign, so we have a plus and a minus in terms of signs.

我们有，我们把这画成一个正的振幅，但因为我们是相消干涉,我们把1sb画成相反的符号，所以我们有一正一负两个符号。

麻省理工公开课 - 化学原理课程节选