Stop being afraid of what could go wrong and start being excited about what could go right.

做一件事和做一件前无古人的事是两码事。

世界是一片伟大的天空，我们是其中的鸟儿。

Democracy is the worst form of government except all those other forms that have been tried from time to time.

数学不是一项观赏性运动。