回复：关于数学，我们还是不要妄自尊大。

Not sure if my daughters can do that. but I did figured them out, partially.
1. I did think the mother's answer was to say the big one is not from a twin;
2. turn on 1st for like 1min, turn it off; turn on 2nd and go upstairs, and touch the light. If it is on then it is the 2nd, if it is off and warm then it is the 1st, if it is off and cool and then it is the 3rd.

所有跟帖： 

• 谢。 -勃事后- ♂ (0 bytes) () 09/22/2009 postreply 15:19:39

• How can you know if the light doesn't work? -霍尔盟- ♂ (0 bytes) () 09/23/2009 postreply 02:11:55