电子式电能表在电压回路加参比电压，电流回路中无电流时，安装式电能表在启动电流下产生一个脉冲的20倍时间内，测量输出应不多于1个脉冲。
参考答案：错
提货单是提取货物的凭证，其作用与提单完全相同。( )
Measures have to be taken to teach young people how to ______ themselves both in family and in school. They don’t know the basic manners.
A．do
B．perform
C．behave
D．work
