最难解释的是每个人都决定不去看的明显事实。
伟大的科学需要聪明的头脑和谦逊的心。
The only limit to our realization of tomorrow is our doubts of today.
"When I write, I aim in my mind not toward New York but toward a vague spot a little to the east of Kansas."
The hardest thing to learn in life is which bridge to cross and which to burn.