be in the know 熟悉内情的，知情的

例句：

Talk to Tim. He's in the know.

跟蒂姆谈谈，他有内幕消息。

Are you in the know about the current crisis?

关于目前的危机，你有什么内幕消息吗？

know better 明白事理，很懂得(而不至于…)

例句：

You know better than to do that!

你明知道不应该那么做!

You are old enough to know better than to spend all your money on clothes.

你年纪足够大了，应当知道不该把钱全花在买衣服上。