最优雅的数学证明是那些以简单揭示真理的证明。

The best investments are those that benefit both people and the planet.

We are never the same with others as when we are alone. We are different, even when we are in the dark.

解释：话说得太甜蜜动听，说话者就必定别有用心。

人们自己创造自己的历史，但是他们并不是随心所欲地创造，并不是在他们自己选定的条件下创造，而是在直接碰到的、既定的、从过去承继下来的条件下创造。