On an average day, nearly everyone fifteen years of age and older took part in a non-work activity like watching television, socializing or exercising.

VOA: special.2011.07.22

Place the non-bonding pairs on peripheral atoms first, which the higher average valence electron energy.

首先将孤对电子放在外围的原子，那儿具有较高的平均价电子能。

麻省理工公开课 - 固态化学导论课程节选