my solution is durable

来源: enchanted 于 2009-09-21 21:00:21 [] [旧帖] [给我悄悄话] 阅读数 : (205 bytes)
本帖于 2009-09-23 04:14:19 时间, 由版主 笑比哭好 编辑
回答: 答第二题 由 transfer 于 2009-09-21 09:40:11

First, turn on two switches then go upstair
If light on, take out the bulb and come down. Measure if there still current go through the switch.
I admit it is not good as your answer but still durable

请您先登陆，再发跟帖！