So when you go ahead and draw these on your problem-sets or on your exams, it's a good idea to put these dashed lines in, both for you and for people reading it to see exactly where your molecular orbitals are coming from.

所以当你在做课后题,或者考试的时候要画这些图时，最好把这些虚线放进去，既方便你自己也方便别人知道,这些分子轨道是从哪里来的。

麻省理工公开课 - 化学原理课程节选