题目

—All the volunteers were very tired, but            of them took a rest.    —They were busy looking for the missing people.    A. neither       B. all     C. both     D. none 答案：D对于电容C=，以下说法正确的是(     ) A.一只电容器所带的电荷量越多，电容就越大 B.对于固定电容器，它所带的电荷量跟它两极板间所加电压的比值保持不变 C.固定电容器的电容跟加在两极间的电压成反比 D.如果一个电容器没有电压，就没有充电荷量，也就没有电容