no one knows for certain信息详情
没有人确切知道
for certain───肯定地；确凿地；无疑地， 确定地
for no one───不为任何人
for knows photos───for knows照片
one no one───一个没人
no one no no───没人不不不
knows───v.知道（know的第三人称单数形式）
no one───n.没有人
certain───pron.某些；某几个；n.(Certain)人名；(葡)塞尔塔因；(法)塞尔坦；adj.某一；必然的；确信；无疑的；有把握的
one for one───一对一
According to Peter Sandiford of the Liverpool School of Tropical Medicine, no one knows for certain.───据利物浦热带医学院的彼得·桑迪福德说，没有人确切地知道。
No one knows for certain how the solar system began.───没有人能确切知道太阳系是如何形成的。
No one knows for certain the origin of the holiday.───没有人确切知道这一节日的来源。
No one knows for certain when the stock market is at an absolute bottom, so you shouldn't waste time trying to guess when that bottom is.───没有人确信知道股票市场什么时候处于绝对谷底，所以你不应该浪费时间去猜测何时是谷底。
Why was he forced to leave native place according to the passage? No one knows for certain.───为什么他被迫离开故里据袭？没有人知道确切的答案。
No one knows for certain what happened, but it's a fair bet that it was not an accident.───没有人知道究竟发生了什么，但几乎可以肯定这并非意外。
No one knows for certain why they like to nest at electrical substations and in utility poles.───无人能够确切地知道它们为什么喜欢在变电站和电线杆上筑巢。
eg. No one knows for certain how many refugees wander the world today, or languish in camps without a permanent place of settlement.───无人清楚如今有多少难民在到处流浪，或有多少人流离失所，在难民营里受苦。
No one knows for certain how many refugees wander the world today, or languish in camps without a permanent place of settlement.
What the purpose of the paintings was, no one knows for certain.