互感器的二次侧必须(),以保证()和()安全。
参考答案:接地;设备;人身
_______ recent report has stated that the number of the WTO member will be over 150 by _____ year 2010.
A. A; the
B.A; /
C. The ; /
D.The; a
测向机对极化波的响应主要决定于所用天线系统,与测向方法无关。