题目

More than twenty _________ students are having an important exam at the moment． A．thousands          B．thousands of           C．thousand             D．thousand of 答案：C如图甲所示的电路，闭合开关后两灯都能发光，并且两块电压表的指针所指的位置如图乙所示，则L1两端的电压是    V，L2两端的电压是    V．