下列哪支血管闭塞最容易导致偏瘫（）
A.小脑后下动脉
B.大脑中动脉
C.脊髓前动脉
D.小脑下前动脉
E.大脑前动脉
参考答案：B
已知两点P1(xl，y1)、P2(x2，y2)，若x1－x2=0，y1+y2=0，则点Pl和P2( )
A．关于x轴对称
B．关于y轴对称
C．关于原点对称
D．以上结论都不对
Housing prices keep rising these years. I’ve got about half the space I had 10 years ago but I have to pay ________now.
A．as three times much
B．three times much as
C．as much three times
D．three times as much
