研究锥管阻力的模型实验,原型进出口直径分别为1m和2m,管长0.5m,则模型管锥顶角为()。
A.45°
B.60°
C.90°
D.120°
参考答案:C
-----Hurry up, you ______ on the phone.
------Oh, I'm coming. Thank you.
A.are wanted
B.are being wanted
C.want
D.are wanting
下列药物中哪些是选择性α-受体拮抗剂类降压药,可治疗顽固性心功能不全()
A.盐酸甲氧明
B.盐酸普萘洛尔
C.盐酸多巴胺
D.阿替洛尔
E.盐酸哌唑嗪