题目

The problem is quite difficult, so ______ students can work it out. A . a few B . a little C . little D . few 答案：D将标有“12V  20W”、“3V  5W”字样的灯L1、L2串联使用．当灯L1正常发光时灯L2会（　　）A．正常发光B．比正常发光暗C．比正常发光亮D．无法判断