know-all

They knew all along that he was packing a gun.

他们向来都知道他身上带着枪。

CASEY SERIN knows all about the excesses of America's housing bubble.

CASEY SERIN非常了解美国房地产市场过沫成分。

We don't know all the circumstances, so it would be pointless to speculate.

我们不了解所有情况, 妄加推测是没有意。

We’re on nodding terms with our neighbours but we don’t know anyone else at all.

我们与邻居是点头之交，不过其他人就不认得了。

I know all these locks seem unnecessary but I believe it’s always better to play safe.

我知道上这么锁似乎没有必要，不过我相信谨慎点总没坏处。