right on the button
正好及时；恰到好处；准确无误
口语·称赞准确或准时
英文释义
exactly correct or accurate; precisely on time or at the expected moment
例句
Your guess was right on the button—it's exactly 100 dollars.
典故来源
源自拳击或射击术语，指击中目标中心，后引申为精准。