粪便隐血试验呈现阳性，每日出血量要达到（）
A.50ml
B.20～30ml
C.10ml
D.5ml以上
E.20ml
参考答案：D
少量风险存在是理想的可保风险应该具有的条件之一。______
______ Nanyue is a small town, we can see many tourists who come from different parts of the world there. [ ]
A. Because
B. Unless
C. Although
