题目

 — How do you like your new head-teacher? —To be frank, I didn’t like him at first, but I ______ my mind. A. have changed      B. was changing         C. had changed           D. would change 答案：A如图，L是自感系数很大的电感线圈（直流电阻不计），L1、L2是完全相同的两个灯泡，则（　　）A．S刚闭合时，L1、L2同时亮且亮度相同B．闭合S达后稳定后，L2熄灭，L1比刚闭合S时更亮C．再将S断开时，L2闪亮一下再熄灭D．再将S断开时，L1不会立即熄灭