题目

 － It seems that Mr Wu is standing there.     － It      be him because he called me from Canada just now. A. mustn’t         B. can’t           C. needn’t        D. shouldn’t 答案：B8．如图所示的电路中，输入电压U恒为12V，灯泡L标有“6V  12W”字样，电动机线圈的电阻0.5Ω．已知灯泡恰好正常发光，以下说法中正确的是（　　）A．电动机的输入功率是12WB．电动机的输出功率是12WC．电动机的热功率是2.0WD．电动机两端的电压是6V