keep one's nose to the grindstone 埋头苦干；锲而不舍

【例句】
Don't give up yet. I'm sure that if you just keep your nose to the grindstone, you'll get the results you want.
别放弃，我确定如果你埋头苦干，你将会得到你想要的结果。

I'm so impressed by your grades, honey—you really kept your nose to the grindstone this year, and it paid off!
我对你的成绩非常钦佩，你今天一直在埋头苦干，它确实带来了好的结果。