下面哪些情况可用β受体阻滞剂()
A.慢性心功能不全,纽约心功能分级3级
B.三度房室传导阻滞
C.慢性阻塞性肺病
D.慢性心功能不全,心率<50次/分
E.急性肺水肿
参考答案:A
With a lot of difficult problems________,the newlyelected president is having a hard time.[ ]
A.settled
B.settling
C.to settle
D.being settled
机械制图的视图分为()。
A.基本视图
B.斜视图
C.局部视图
D.旋转视图