Definition
To have a very thorough and detailed understanding of something.
熟能生巧
He knows the history of this city back to front.
他對這座城市的歷史瞭若指掌。
The chef knows the origins of all the ingredients back to front.
這位廚師對所有食材的來源瞭若指掌。
She can recite the entire textbook, knowing it back to front.
她可以背誦整本教科書，對它瞭若指掌。