题目

某同学利用如图所示电路进行实验，闭合开关后，L1和L2正常发光，两个电表都有示数。但过了一会儿后，两个电表的示数都变为零，这时电路发生的故障可能是( ) A. 电压表断路 B. 电流表断路C. 灯泡L1断路 D. 灯泡L2断路 答案：【答案】B【解析】由图可知，灯泡L1、L2并联，电流表测L1支路的电流，电压表并联在灯泡L1两端。闭合开关后，L1和L2正常发光，两个电表都有示数。但过了一会儿后，两个电表的示数都变为零。A、如果是电压表断路，则电路是连通的，两灯泡正常发光，电流表有示数，故A不符合题意；B、如果是电流表 Excuse me, but could you tell me ________?I'd like to drop him a line． [　　] A． where is his address B． where his address is C． what his address is D． what is his address