Turn on the first for one min and then turn it off.9 p+ f2 S3 O3 I- t) y' e5 J' [ G2 U
Turn on the 2nd for five min and then turn it off. & b. ?% f% \% h% @7 ATurn on the 3rd and leave it on.5 }+ Z. m( [- |$ N
And then go upstairs right away. - l+ Z. m( y6 h% k+ d% U# y* C* }1 Z& G% o9 ?+ h( W: U* @; r7 V3 L
Find the answer by using your fingers and eyes# P0 n4 X0 P' l) m9 q9 y3 V
这只是一个智力问题,不象是电工问题。
原帖由 老警察 于 2009-1-16 07:12 发表 3 g+ S' R5 o4 @( J. d3 Y1 J
Turn on the first for one min and then turn it off. 9 W f9 ^% o/ H1 y- }Turn on the 2nd for five min and then turn it off.! u3 s9 f7 w/ N
Turn on the 3rd and leave it on.& p1 c: }; o5 t" `! L
And then go upstairs right away.& J6 {9 |+ d; ? x