证明是一种用于使他人相信数学陈述为真的工具。
The only way to discover the limits of the possible is to go beyond them into the impossible.
永远不要放弃你的梦想。
Take long walks in stormy weather or through deep snows in the fields and woods, if you would keep your spirits up. Deal with brute nature. Be cold and hungry and weary.
The companies that will thrive are those that see conservation as an investment, not a cost.