缄默：只说对人对己有益的话，避免闲聊。
Natural experiments can provide valuable insights into economic questions.
Challenges are what make us grow; embrace them.
The stories we tell ourselves about ourselves are the most powerful stories of all.
The world is a place of infinite complexity, and we are all just trying to make sense of it.
实现不可能的唯一方法就是相信它是可能的。