know one's onions

精通某一领域

You sure know your onions,buddy!

你应该有所精通

You sure know your stuff, buddy!

你应该有所精通

If you want advice on stocks,go ask Livermore,he has an excellent track record and he certainly knows his onions.

如果你想要股票方面的意见，去问问利弗莫尔好了，它的历史记录一直很好，绝对精通这个领域。

It's not surprising that Yi zhongtian and Yu Dan are so phenomenally popular these days.

易中天和于丹能如此受欢迎乃在情理之中。

They sure know their onions.

他们非常精通自己讲解的东西。