Optimal fiscal policy requires that tax rates be smooth over time, responding only to permanent changes in government spending.
最优财政政策要求税率随时间平稳变化，仅对政府支出的永久性变化作出反应。
Don’t worry about others not understanding you. Worry about you not understanding others.
There is no such thing as society: there are individual men and women, and there are families.
创新不是一蹴而就的，而是需要持续不断的努力和积累。