决策理论学派的代表人物是（）
A.韦伯
B.孔茨
C.巴纳德
D.西蒙
参考答案：D
已知AB为⊙O的一条弦，长为12cm，则圆O的半径r的取值范围是 [ ]
A.大于6cm
B.小于6cm
C.大于或等于6cm
D.不能确定
He kept thinking of the question whether it was ____ for his father to change the habit of a life time in such a short time.
A．possibly
B．probable
C．likely
D．possible
