Sustainability isn't a buzzword; it's the foundation of modern resource extraction.

The best way to guarantee a loss is to quit.

凡是大国之所以不攻打小国的，必定是由于这个小国粮食充足，城郭修筑坚固，上下和谐一心。 

经济模型的价值在于其解释和预测的能力。