愉快是健康的最佳促进者。
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。
The most sustainable building is the one that is already built.
Make women rational creatures, and free citizens, and they will quickly become good wives; — that is, if men do not neglect the duties of husbands and fathers.
阈限性是两个阶段之间的过渡状态,个体不再处于前一个状态,但尚未进入下一个状态。