know one's ABCs 了解基础的知识

例句：

I don't think he should do this. He doesn't even know his ABCs.

我认为他不应该做这个，他对此一无所知。

Do you know the ABCs of programming?

你了解编程的基础知识吗?

know someone or something like a book 熟悉，深知，对…了如指掌

例句：

She knows Jerry like a book.

她非常了解杰瑞。

We've been married now for thirty years-long enough to know my wife like a book.

我们已经结婚30年了，我对我的妻子是非常了解的。