社会不知道怎样处置惯犯。
Society does not know how to deal with hardened criminals.
他知不知道有什么关系吗？
What difference will it make if he knows or not?
她不知道自己如何弄得如此狼狈不堪。
She wondered how she had got into this unholy mess.
我不知道该不该穿外套。
I wonder if I should wear a coat or not.
我们不知道他是死是活。
We don't know whether he's alive or dead.