know somebody/something inside out
US /noʊ ˈsʌm.bə.di ˈsʌm.θɪŋ ˌɪn.saɪd ˈaʊt/
UK /noʊ ˈsʌm.bə.di ˈsʌm.θɪŋ ˌɪn.saɪd ˈaʊt/
1.
了如指掌, 非常熟悉
to know someone or something extremely well
:
•
She's worked here for twenty years, so she knows the company inside out.
她在这里工作了二十年，所以她对公司了如指掌。
•
He's a local, so he knows this area inside out.
他是本地人，所以他对这个地区了如指掌。