自然实验可以为经济问题提供有价值的见解。
Natural experiments can provide valuable insights into economic questions.
在这个世界上,有些东西用石头是刻不来的。在我们的心中有块地方是关不住的,那块地方称为自由。
The propensity to truck, barter, and exchange one thing for another is common to all men, and to be found in no other race of animals.
The true cost of inequality is the potential that goes unrealized.