大脑底面（）。
A.大脑前动脉供血
B.大脑中动脉供血
C.大脑后动脉供血
D.椎动脉供血
E.基底动脉供血
参考答案：C
We must make ( ) that the goods were packed in gunny bags of 50kgs net each.
A．clear
B．it clear to you
C．clear to you
D．it is clear
金属材料的理化性能有（）
A.密度
B.导热性
C.导电性
D.抗拉强度
