题目

We shouldn't complain about being poor because many families are much _______ off. A . badly B . bad C . worse D . worsely 答案：C如图所示，当开关S闭合时，电压表的读数为3V，电流表的读数为0.1A，那么R=    Ω，当开关断开后，电路中的电流为0A时，R=    Ω．