—— 请按键盘 空白键 开始游戏 ——

Mathematics is not a spectator sport. You have to do it to understand it.
I'm a great believer in luck, and I find the harder I work the more I have of it.
持续的部分注意力是一种始终在线、随时随地、任何地方的行为,涉及一种人为的持续危机感。