What you'll actually find in terms of asking your TAs about the Lewis structure rules is that sometimes they won't be as good at them as you are, and the reason is once you've drawn enough of these structures, you start to get a lot of chemical intuition about it just looks wrong to you if it's wrong.

其实如果大家去问助教,路易斯结构的规则是什么的话,你会发现他们有时候可能并不比你们记得更清楚，因为一旦你画过足够多的路易斯结构，你就会开始获得很多化学直觉,如果它是错的，那么对你来说它看起来就是错的。

麻省理工公开课 - 化学原理课程节选