同步电动机可以采用（）的运行方式，在电网中改善电网的功率因数和减小电网电压波动做调相机使用。
A、欠励
B、欠复励
C、过励
D、复励
参考答案：C
— Excuse me,sir. Would you do me a favour?
— Of course. What is it?
— I ________ if you could tell me how to fill out this form. [ ]
A. had wondered
B. was wondering
C. would wonder
D. did wonder
悬空作业应由牢靠的立足出，并必须视具体情况配置（）或其他安全设施。
A、立网
B、栏杆
C、防护栏网
D、安全警告标志
E、安全钢丝绳
