軍武

美國入侵伊拉克和阿富汗戰爭的策劃者拉姆斯菲爾德去世，終年88歲

據我們所知，我們已經知道一些，我們知道我們已經知道一些。
As we know, there are known knowns;
我們還知道，我們有些並不知道，也就是說，我們知道有些事情我們還不知道。
there are are things we know we know. we also know there are known unknowns;that is to say we know there are some things we do not know.
但是，還有一些，我們並不知道我們不知道，這些我們不知道的，我們不知道。
but there are also unknown unknowns---the ones we don't know we don't know.