下列不是电能质量指标的是。（）
A.电压；
B.频率；
C.电流；
D.波形
参考答案：C
固定资产由于毁损而转入清理，按清理固定资产的净值，借记“营业外支出”科目，贷记“累计折旧”和“固定资产”科目。( )
We were listening closely to the lecture yesterday evening when suddenly the light ________. [ ]
A. had been gone out
B. go out
C. was gone out
D. went out
