自然实验是理解现实世界中因果关系的强大工具。
Natural experiments are a powerful tool for understanding causal relationships in the real world.
The best stories are those that ask questions, not answer them.
在严冬之中，我发现，在我心中，有一个不可战胜的夏天。
My characters are not innocent. They know too much.
The web is a reflection of our society and a window into our souls.
If you're going to build a brand, you have to be relentless in your pursuit of excellence.