我们只是试图解决一个需要解决的问题。
自然实验可以为经济问题提供有价值的见解。
对天资在中等程度以上的人，可以和他谈论高深的学问；而对于中等以下天资的人，则不可以和他谈论高深的学问。
The aim of every artist is to arrest motion, which is life, by artificial means and hold it fixed so that a hundred years later, when a stranger looks at it, it moves again since it is life.
权力从来不是无辜的，无辜从来不是强大的。
Monsters are real, and ghosts are real too. They live inside us, and sometimes, they win.