名詞 grindstone:

1. a revolving stone shaped like a disk; used to grind or sharpen or polish edge tools

1. The teacher believed in hard work and always keep our nose to the grindstone.
   老師提倡勤奮，而且也總是要我們埋頭讀書。
2. I always admire men, even the dullest, who know their job and put their noses to the grindstone.
   我一向敬重那些有專長且做事勤奮不懈的人，包括那些最沒情趣的人。
3. Our factory produces grindstone.
   我們工廠生產磨刀石。
4. They ground the knife on a grindstone.
   他們在磨刀石上磨刀子。

grind.stone

n.（名詞）
A revolving stone disk used for grinding, polishing, or sharpening tools.
砂輪：用來打磨、打光或磨利工具的旋轉石盤
A millstone.
磨石

<習慣用語>put (one`s) nose to the grindstone【非正式用語】
To work in earnest.
認真地工作