We all know some drop-dead beautiful person married to an unusually plain wallflower.This is a trade-off some call the equity theory.

• 大家都知道，也有些光彩照人的“宠儿”与那些平平无奇的“丑小鸭”走入婚姻的殿堂，这或许就是人们所说等价平衡理论吧。