The best time to plant a tree was 20 years ago; the second best time is now.
Protecting marine resources is protecting the future of humanity.
The only way to do great work is to love what you do.
使用程序证明四色定理不会改变数学-它只是表明该定理是一个世纪的挑战,对数学可能并不重要。
The whole honours and pride in the world, all come from the mother.
现实与幻觉之间的界限常常模糊不清。