电动机的额定功率是指电动机额定工作状况下运行时轴上能输出的机械功率。
参考答案：对
The policeman came up to the house, whose door was open, _____ there for a while, and went in.
A．to stand
B．standing
C．stood
D．stand
密度测井是利用电子对效应测定地层密度的测井方法。
