大脑前动脉分为5段，即_______、_______、_______、_______和_______。
参考答案：水平段、 上行段 、膝段 、胼周段、 终段
— Jenny, how many years have you studied in China?
— I ________ here for three years by the end of this month.
A．study
B．have studied
C．will have studied
D．am studying
下列哪项不是呼吸衰竭导致肺性脑病的机制
A．PaO2下降引起脑血管扩张
B．PaCO2升高引起脑血管扩张
C．缺氧、酸中毒使脑血管通透性增高，脑水肿
D．合并休克
E．脑细胞内广氨基丁酸生成增多
