免费游戏最贵的成本是玩家的信任,一旦透支就再也买不回来。
The nervous system is like an intricate orchestra, with each neuron playing its part.
The pursuit of mathematical knowledge is a journey that never ends.
一个有纸、笔、橡皮擦并且坚持严格的行为准则的人,实质上就是一台通用图灵机。