清洁：身体、衣服及住所，力求整洁。

Men marry because they are tired, women because they are curious; both are disappointed.

The only limit to our realization of tomorrow is our doubts of today.

All men are created equal.

我不害怕说出自己的想法，即使它不受欢迎。

I write to remember, to keep alive what would otherwise be lost.

The best science is done with both the head and the heart.

经济增长和环境责任之间的平衡是我们这个时代的决定性挑战。

时间是我们能够感知变化的唯一维度。