类和对象都有属性，它们的差别是：类描述了属性的类型，而对象的属性必须有（）。
A.正负号
B.动作
C.具体值
D.私有成员
参考答案：C
surprises most of us.
A．Wolves are afraid of us
B．The fact that wolves afraid men
C．The fact that wolves are afraid of men
D．Wolves’ afraid of men
治疗肝豆状核变性病首选的药物是
A．青霉胺B．二巯基丙醇C．谷胱甘肽D．促排灵E．亚甲蓝
