这句话什么意思?there are known knowns,there are also unknown unknows..
这是美国国防部长拉姆斯菲尔德在去年2月在一次记者招待会上谈到伊拉克是否存在大规模杀伤性武器时向媒体说的一段话：“Reports that say that something hasn't happened always interesting to me ,because as we know ,there are known knowns ;there are things we know we know .We also know there are known unknows ;that is to say we know there are some things we do not know .But there are also unknown unknowns — the ones we don't know we don't know .”（“我一向对尚未发生的事情的有关报道感兴趣,因为就像我们都知道的那样,有一些众所周知的事情；我们知道一些我们知道的事情.我们还知道一些很明显的未知事情.那就是说,我们知道有些事情我们不知道.但也有没人知道的未知事情——也就是我们不知道的未知事情.”）
