Lines 82 and 83 draw a dotted line at the top and halfway down the Y-axis. This simply makes the graph easier to read.

第82和83行在y轴的顶端和中间各划一条水平虚线，这样做只是为了让查看图时更方便。

youdao

Analyze this sentence. Draw a line under the subject, a double line under predicate, a wavy line under the attribute, and a dotted line under the adverbial.

分析这个句子。在主语下划横线，在谓语下划两道横线，在定语下划曲线，在状语下划虚线。

youdao

Analyze this sentence. Draw a line under the subject, a double line under the predicate, a wavy line under the attribute, and a dotted line under the adverbial.

分析这个句子。在主语下划道横线，在谓语下划两道横线，在定语下划曲线，在状语下划虚线。

youdao

But since in drawing Lewis structures actually, in some cases you do, you can draw a dotted line that means a 1 and 1/2 bond, but most in most cases, we just draw out both resonance structures, and the way that we say it's a resonance structure is that we put it in the brackets and we put an arrow between it.

但是由于在画路易斯结构时,其实，在某些情况下是可以的，你可以画一条虚线来表示一又二分之一键，但是在多数情况下，我们就把两个结构都画出来，而我们说这是一个共振结构的表示的方法是,把它们放在括号里，并在中间放一个双箭头。

麻省理工公开课 - 化学原理课程节选