便血的概念
参考答案：
便血是指消化道出血，血液由肛门排出。少量的消化道出血，每日5ml以下，无肉眼可见的粪便颜色改变者称为隐血。
___ three times in a row, the boxer decided to make a fourth attempt, though．
A．Having defeated
B．To have defeated
C．Having been defeated
D．To defeat
“苏格拉底方法”是一种什么方法？
