I insisted _____ to see a doctor, but he insisted nothing ____ wrong with him.

A．on him to go; should be

B．he went; be

C．he go; was

D．he should go; is

下列使用投影机的正确操作有（）

A.同时切断投影机电源和投影机灯泡的电源

B.投影机灯泡上的污迹可以用透镜纸擦拭

C.较长时间不使用投影机，应切断投影机电源

D.严禁搬动处于工作状态的投影机