哪一种改变能引起继发性椎管狭窄（）
A.黄韧带肥厚
B.椎间盘向后膨隆
C.椎体后缘骨质增生
D.椎小关节增生
E.以上都是
参考答案：E
Don't you recognize him? Just look up. On the opposite wall ________.
A．does his photo hang
B．hangs his photo
C．is hanging his photo
D．is his photo hanging
关于拟肾上腺素药的叙述错误的是
A．多巴胺可激动α、β及多巴胺受体
B．去甲肾上腺素主要激动α受体，对β1受体也有一定的激动作用
C．麻黄碱可激动α、β受体
D．肾上腺素可激动α、β受体
E．异丙肾上腺素可激动α、β受体
