If we spoke a different language, we would perceive a somewhat different world.
The secret of happiness is freedom, and the secret of freedom is courage.
The hardest thing is to live richly in the present without letting it be tainted by the past or future.
The mathematician's patterns, like the painter's or the poet's, must be beautiful; the ideas, like the colors or the words, must fit together in a harmonious way.
可持续林业不是一种选择;它是一种义务。