解释：对事物最好的证明是有效果，对论点最好的认定是有证据。
The microbe is nothing; the terrain is everything.
We are all alone, born alone, die alone, and—in spite of True Romance magazines—we shall all someday look back on our lives and see that, in spite of our company, we were alone the whole way.
The best way to learn econometrics is by doing—working with real data and real problems.
