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The best solutions come from listening to those who work the land every day.

A good mathematician is someone who can see analogies between theorems. A great mathematician is someone who can see analogies between analogies.

The past is never dead. It's not even past.

理智是不朽的，其他一切都是有限的。

工具變量的美妙之處在于它們讓我們以新的視角看世界。