You have to know what's what and when to draw the line.

你必须搞清状况以及自己的底线。

柯林斯例句

You've old and pigheaded. You don't know what's what.

你真被迷了,老昏了,一点也不会想了.

汉英文学 - 中国现代小说

I guess I'm your auntie and I know what's what.

不管怎么说,我总是你的姑妈,也不是不明事理.

飘（部分）

You're old enough now to know what's what.

你已经不小了,应该知道好歹了.

辞典例句

In the choice you need to know what's what.

在选择上也需要您心里有数.

互联网

If you want to know what's what.

你需要几个星期的功夫才能熟悉这项工作.

互联网

With all his experience in the trade, he should know what's what where wines are concerned.

根据他的经商经验, 他应该有分辩酒类好坏的能力.

互联网

More than that, we shall have a tempest, or I don't know what's what.'

不止大风, 我们要遇到的是一场暴风, 不然就算我看走眼了.

互联网