In Vivian's case, her unit of production isn't the tangible hours she works, it's the intangible difference she makes during that one hour of work.
从薇薇安的例子中， 她的单位产量 并不是可以计算的她工作的每个小时 而是她所做到的那些不可触摸的区别 在那一小时的工作中