自然实验可以为经济问题提供有价值的见解。
我认为最重要的是享受你所做的事情。如果你享受它,那么你就会做得好。
In heaven, all the interesting people are missing.
过去是一个异国;他们在那里做事的方式不同。
You never know with these things when you're trying something new what can happen. This is all experimental.