题目

电路中形成电流的条件是（     ） A．电路两端要有电压            B．电路是闭合的 C．电路两端既要有电压，且电路又是闭合的       D．电路中要有电子 答案：C—Why are you so happy?       — Jim says I am clever. ______ has ever told me that before. [     ]A. Anybody B. Somebody C. Nobody D. Everybody