下列属于旧机电产品的有______。
A．旧打印机 B．旧电饭锅C．旧钢轨 D．旧船用桌椅
参考答案：A,B
She is the only one of the students _______ able to answer this question.
A．who is
B．who are
C．that is
D．that are
A．副线圈中电压表的读数为55V
B．副线圈中输出交流电的周期为0.01s
C．原线圈中电流表的读数为0.5A
D．原线圈中的输入功率为110W
W