题目

(1)下表为某电热水壶铭牌上的一部分内容。根据表中的信息，可计算出电热水壶在额定电压下以额定功率工作时的电流约为____________。型号DF-938额定功率900W额定电压220V额定容量1.2L A．6.8A B．4.1A C．1.2A D．0.24A(2)在家庭电路中洗衣机和电冰箱是____________（填串联或并联），节能灯比白炽灯的发光效率____________（填高或低）。　　——I have stayed here for two years. 　　——Really? Then you ________ the city quite well. [　　] A．must have known B．should have known C．can know D．may know