Mathematics is not a spectator sport. You have to do it to understand it.
数学不是一项观赏性运动。你必须亲自去做才能理解它。
Courage in monetary policy is not the absence of fear but the judgment that something else is more important than fear.
Believe that life is worth living, and your belief will help create the fact.
想象是创造的开始。你想象你所渴望的,你意愿你所想象的,最终你创造你所意愿的。