下定决心用英语怎么说

"Make up one's mind" 是一个常见的表达，用来表示下定决心。这个短语源自古英语中的 "gemot"，意为"会议"，后来引申为"商量、决定"。
例句：
I need to make up my mind about what to do next. 我需要决定下一步该做什么。
She finally made up her mind to go to graduate school. 她最终下定决心去上研究生院。
He's still trying to make up his mind about whether to take the job. 他仍在考虑是否接受这份工作。