肾盂肿瘤首选检查方法为()
A.B型超声
B.逆行输尿管造影
C.IVP
D.KUB
E.CT
参考答案:C
在安装大型注水电动机轴承时,其轴承底座下面应加装()。
A、铜垫片
B、铝垫片
C、铁垫片
D、绝缘垫片
When I am in difficulty, I always ____ him for help. [ ]
A. turn out
B. turn over
C. turn to
D. turn on