数学不是观赏性运动，你必须参与其中才能理解。
"Imagination is not only the uniquely human capacity to envision that which is not, and therefore the fount of all invention and innovation. In its arguably most transformative and revelatory capacity, it is the power that enables us to empathize with humans whose experiences we have never shared."
The desert could not be claimed or owned–it was a piece of cloth carried by winds, never held down by stones, and given a hundred shifting names.
The more you sweat in practice, the less you bleed in battle.
The key to successful trading is to know when to buy and when to sell.
