be in the know
英英解释: have inside knowledge about a situation
Talk to Tim. He's in the know.
Are you in the know about the current crisis?
英英解释: have knowledge about how one should behave
You know better than to do that!
I wish he had acted differently. He certainly knew better!
英英释义: understanding of how a task should be done
I'd call technical support and ask someone with the know-how.
Do you have the know-how to upgrade our servers?
know the tricks of the trade
英英释义: possess the skills and knowledge to be successful in a particular task
Let's ask Tom. He knows all the tricks of the trade.
I think we need to bring in a specialist who knows the tricks of the trade.
know one's ABCs
英英释义: to understand and be capable of doing the basics
I don't think he should do this. He doesn't even know his ABCs.
Do you know the ABCs of programming?
know someone or something like a book
英英释义: completely understand someone or something