know your stuff
US /noʊ jʊər stʌf/
UK /noʊ jʊər stʌf/

成语
1.
很懂行, 精通
to be very knowledgeable and skilled in a particular area or subject
示例:
•
You can trust her advice; she really knows her stuff when it comes to financial planning.
你可以相信她的建议;在财务规划方面,她确实很懂行。
•
The new mechanic clearly knows his stuff; he fixed the engine in no time.
这位新机械师显然很懂行;他很快就修好了发动机。
在 Lingoland 学习这个单词