对于理想变压器，当副边开路时，其原边电流和输入的视在功率分别是（）。
A．0／额定值
B．∞／额定值
C．∞／∞
D．0／0
参考答案：D
What do you do? [ ]
A. I'm Miss White.
B. I'm a teacher.
C. I go to school every day.
根据汉语提示完成句子。
1. I need to____ ____ ____ ____ (偿清所有债务) before I leave the country.
2. They are poor but they never____ ____ ____（负债）.
