Definition
to commence working diligently
着手专心工作
Before the exam, I decided to buckle down and study hard to improve my grades.
在考试前，我决定认真学习，以提高我的成绩。
He realized that if he didn't buckle down, he would never finish the project.
他意识到如果不认真工作，他永远也无法完成这个项目。
We need to buckle down right now; otherwise, the deadline will creep up on us.
我们现在需要认真工作；否则，截止日期会悄悄逼近。