题目

—What’s Mary like?   —______________________.      A. She is a helpful girl              B. She feels better now      C. She is a teacher                 D. She likes singing 答案：A在“测定小灯泡额定功率”的实验中，当手移动变阻器滑片时，眼睛应观察（ ）A．灯泡的发光情况B．变阻器滑片的位置C．电压表的示数D．电流表的示数