You walked home alone? Don't you know better (than that)?你独自走回家的？难道你没脑子吗？

She'll know better than to trust them again. [=she will not trust them again]她不会再相信他们了。

There's no excuse for his behavior. He's old enough to know better.他的行为不可原谅。他这么大，应该懂事了。

Don't blame him. He's just a child and he doesn't know (any) better. [=he is too young, inexperienced, etc., to be expected to behave properly]别责怪他，他还是个孩子，不懂事。

She tried to tell me that it wasn't her fault, but I know better. [=I know that it really was her fault]她试图告诉我那不是她的错，但我知道是怎么回事。

You can't tell him what to do. He always thinks that he knows better.你不能告诉他该做什么，他总认为他比谁都明白。