know what's what

US /noʊ wʌts wʌt/
UK /noʊ wʌts wʌt/
"know what's what" picture
1.

知道是怎么回事, 了解情况

to have a good understanding of a situation or of how things work

:
She's been in this business for years, so she really knows what's what.
她在这个行业多年,所以她真的知道是怎么回事
You need to spend some time learning the ropes if you want to know what's what around here.
如果你想在这里知道是怎么回事,你需要花一些时间学习窍门。