The historian’s first duty is to the truth.

The greatest untapped resource in the global economy is the full participation of women.

The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.

The core of technological innovation is to solve practical problems, not to innovate for the sake of innovation.

朋友比钱更好。几乎所有金钱能做的事情，朋友都能做得更好。在许多方面，有一个有船的朋友比自己有一艘船要好。

可持续性是采石业的未来，我们必须立即行动。