I don't know about all this.
この一件のことは知らない
I don't know about you, but ....
君はどう思うか［どうだか］知らないが…
I don't know anything yet.
まだ何も知らない
I don't know both of them.
両方は知らない［一方だけ知っている］
I don't know either of his brothers.
彼の兄弟のどちらも知らない
I don't know for certain what her profession is.
彼女の職業をはっきりとは知らない
I don't know nothing.
何も知らない（◆否定を強めて）
I don't know the first thing about it.
そのことについては皆目知らない
I don't know.
知らない；それはどうかなあ
I don't understand about how to manage it.
うまい対処法を知らない
