Natural experiments can provide valuable insights into economic questions.
自然实验可以为经济问题提供有价值的见解。
活着就要全力以赴,不留遗憾!这生活的态度,太鼓舞人心了!并且我们应该活在当下,尽全力去做每一件事!
过去从未消逝,它甚至从未成为过去。
The Langlands program is not a static set of conjectures but a dynamic field of research.