know better

: to be smart or sensible enough not to do something有头脑，明事理（而不至于…）

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。

: to know or understand the truth about something了解（或知道）真相

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。

: to know or understand more than other people比别人都明白（或了解）

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。

⇒ Main Entry: ¹ know

idiom

: to be smart or sensible enough not to do something

You walked home alone? Don't you know better (than that)?

She'll know better than to trust them again.

There's no excuse for his behavior. He's old enough to know better.

Don't blame him. He's just a child and he doesn't know (any) better.

: to know or understand the truth about something

She tried to tell me that it wasn't her fault, but I know better.

: to know or understand more than other people

You can't tell him what to do. He always thinks that he knows better.