以下哪些有利于肺源性心脏病的诊断()
A.ORS低电压
B.二尖瓣型P波
C.Rv1=1.2mVR/S>1
D.PⅡ高尖,振幅>1/2R
E.ORS电轴-15°
参考答案:A, C, D
— How long has your brother been working in this factory?
— he graduated from college.
A.When
B.By the time
C.Until
D.Ever since
只有明确模型的( ),才能有的放矢,以合理的条件和方法建造模型。
A.依据
B.规格
C.功能
D.色彩