He is always telling the director how to run the business; that's like teaching one's grandmother how to suck eggs.

他经常告诉主任如何经营, 这岂不是班门弄斧吗?

《简明英汉词典》

Don't try to teach your grandmother to suck eggs.

不要教你祖母吸鸡蛋.

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Don't teach your grandmother to suck eggs!

不要班门弄斧!

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Teach your grandmother to suck eggs.

班门弄斧.

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You can't teach grandma to suck eggs.

没牙的婆婆吸得出蛋.

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Do not teach your grandmother to suck eggs.

不要班门弄斧.

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