不要害怕为你相信的东西独自站立。

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.

自然和历史是地理知识的两个重要来源。

Why do I stand up here? I stand upon my desk...to remind myself that we must constantly look at things in a different way.