直流发生接地故障时禁止在二次回路上工作。
参考答案:对
—They is an look on his face. What for?
—Because he heard the news about his students just now.[ ]
A. excited; exciting
B. exciting; excited
C. excited; excited
D. exciting; exciting
一阶环节传递函数式为()。
A、A
B、B
C、C
D、D