And step four is going to have us figure out how many bonding electrons we have, so we have 16 minus 10, is going to be 6 bonding electrons.

而第四步需要判断,我们有多少个成键电子，那么我们有十六减十，也就是六个成键电子。

麻省理工公开课 - 化学原理课程节选