题目

As a result of the serious flood, two-thirds of the buildings in this area _____.      A. needs repairing                                   B. need to be repaired   C. need being repaired                             D. needs to repair 答案：B 解析: 略某同学利用电源、电流表、电压表、开关，标有“50Ω 2A”字样的滑动变阻器和若干导线测定小灯泡的额定功率。其中灯泡上所标“0.3A”字样清晰可见，电压表0～15V挡损坏，小灯泡的额定功率估计为1.5W左右。画出灯正常发光的电路图，并简述判定灯正常发光的理由；