题目

The police officer stopped us and asked us where         .   A. were we going  B. we were going  C. are we going  D. we are going 答案：B5．如图所示电路，电源电压不变，闭合开关，当滑动变阻器R的滑片向下移动时，电压表V1的示数不变；电压表V2的示数变小；电流表的示数变小；电路消耗的总功率变小（以上四空均选填“变大”、“变小”或“不变”）．