To live is to endure, to find meaning in the chaos, and to keep moving forward despite the pain.

They had said that the city was a paradise, but I found it a hell.

释义：圆的器物容易滚动，而方的器物则易于停止，这是器物的差异；金属刚硬而水则柔弱，这是它们的物性不同。

The best way to learn econometrics is by doing—working with real data and real problems.

The language of mathematics is universal, transcending cultural and linguistic barriers.