—— 请按键盘 空白键 开始游戏 ——

Why does a person own a dog?”“For security, I guess...For the security of knowing that there's at least one creature in the world who likes you.
理解布莱克-斯科尔斯模型的关键在于认识到它是基于创建无风险对冲的理念。
悲伤不是线性的。它不会整齐地从否认走向接受。