题目

 --- You look so young. Haven’t you graduated from your university?     --- Yes, I _______ in the English Department of Zhejiang Normal University for four years.       A. was studying             B. study                   C. had studied        D. studied 答案：D汽车中有如图所示的电路，其中上端带金属细杆的金属滑块M与两侧金属弹簧相连并接人电路中，金属滑块M与弹簧套在光滑绝缘的水平细杆上．当汽车静止时，滑块M上的金属细杆与红、绿灯一端的触头都不接触．当汽车向前启动时，______灯亮；当汽车急刹车时，______灯亮．上述设计中应用到了一切物体都具有______这一物理知识．