I still remember ______ to the Science Museum for the first time when I was young.

A．to take

B．having taken

C．taking

D．being taken

如图所示，闭合开关，电灯不亮，用试电笔（也称测电笔）接触D点时氖管发光，接触E点时不发光，说明D、E间____________。若试电笔接触A至F各点都发光，说明____________。