组合数学就像是不用实际计数的计数艺术。
Combinatorics is like the art of counting without actually counting.
The hours of folly are measured by the clock, but of wisdom: no clock can measure.
Innovation and technology will be key to meeting the world's growing energy needs while reducing environmental impacts.
你想用卖糖水来度过余生,还是想要一个机会来改变世界?