我听说楚地有一只神龟，已死三千年了，楚王用布包好，再用竹编把它装着，藏在庙堂之上。这龟，宁愿死了尊贵地保留着骸骨呢，还是宁愿活着在泥水中摇曳着尾巴？

A proof is a device for convincing someone else that a mathematical statement is true.

Sustainability isn't a choice anymore—it's the only way forward for responsible businesses.

The most important decision you make is to be in a good mood.