The beauty of instrumental variables is that they allow us to see the world in a new light.
工具变量的美妙之处在于它们让我们以新的视角看世界。
The only way to deal with the past is to confront it.
"I am the best me there is. I think I’m pretty cool."
历史不会原谅遗忘。
解释:先前所使用的,现在或许要抛弃。现在要抛弃的,将来或许会用到。
Success comes when you focus on the customer, not the competition.