以三偏征为特征的动脉闭塞是（）。
A.颈内动脉闭塞
B.主干闭塞
C.皮层支闭塞
D.深穿支闭塞
E.大脑前动脉闭塞
参考答案：B
— Which book would you like to borrow?
— ______ of the two books is OK with me. [ ]
A. Either
B. Both
C. Any
D. None
1.5m2=15000（）。
A、dm2
B、cm2
C、mm2
D、μm2
