可持续性不是一种选择；它是农业未来的必要条件。

学习计量经济学的最佳方法是通过实践——处理真实的数据和真实的问题。

The end of history will be a very sad time. The struggle for recognition, the willingness to risk one's life for a purely abstract goal, the worldwide ideological struggle that called forth daring, courage, imagination, and idealism, will be replaced by economic calculation, the endless solving of technical problems, environmental concerns, and the satisfaction of sophisticated consumer demands.

我不是为观众画画，我是为我自己画画。