1/2
所有跟贴·加跟贴·新语丝读书论坛
送交者: HunHunSheng 于 2008-07-31, 23:35:34:
回答: 什么是你的解答? 由 JFF 于 2008-07-31, 23:24:00:
You have to take into consideration that both girls and
boys are equally likely to make a noise. if you only hears boy's voice that means it raise probility that both are boys
所有跟贴:
加跟贴