around the clock

around 是围绕的意思，clock 是钟表，围绕着钟表不停转，就是 all day and all night without stopping，around the clock 中文意思就是“全天候” “夜以继日地” “昼夜不停地” “不眠不休地”。

More than 500 firefighters were working around the clock to contain the blaze.

500多名消防队员日以继夜的工作来控制火势。

They were willing to work around the clock, sleep in the office and battle each other over strategy and technical decisions.

他们都愿意没日没夜地工作，愿意睡在办公室里，还愿意为公司的战略和技术决定相互争吵。

They are studying around the clock when they are preparing for the final exam.

他们在准备期末考试的时候，夜以继日地学习。

Some stores stay open around the clock, while others do business for only a few hours a day.

有些商店昼夜营业，有些每天只开门营业几个小时。

She's working around the clock to meet the deadline.

为了在截止日期前做完，她在一刻不停的工作。

against the clock

against the clock 意思是争分夺秒、尽可能快，常和 work 和 race 搭配。