teach your grandmother to suck eggs

US /tiːtʃ jʊər ˈɡrændˌmʌðər tə sʌk ɛɡz/
UK /tiːtʃ jʊər ˈɡrændˌmʌðər tə sʌk ɛɡz/
"teach your grandmother to suck eggs" picture
1.

班門弄斧, 教導比自己更有經驗的人

to try to teach someone something they already know, especially someone who is more experienced than you

:
I tried to explain how to use the new software to my boss, but it was like teaching my grandmother to suck eggs; she's been using similar programs for decades.
我試圖向老闆解釋如何使用新軟體,這就像班門弄斧;她使用類似的程式已經幾十年了。
He started giving me advice on cooking, but I've been a chef for twenty years. It was definitely a case of teaching your grandmother to suck eggs.
他開始給我烹飪建議,但我已經做了二十年廚師了。這絕對是班門弄斧