全部运算在三秒内完成。

The whole operation is performed in less than three seconds.

《牛津词典》

这是我一周内的第三次来访，这本身就说明了一切。

This is my third visit in a week, which says it all.

《柯林斯英汉双解大词典》

但肯定会在三周内发生。

But it will certainly be within three weeks.

youdao

What you should imagine doing is making these three measurements more and more quickly.

你应该想到的做法,是在尽量短的时间内完成这三次测量

耶鲁公开课 - 基础物理课程节选

But it's only an effective vaccine in the context where you have people who can go to the doctor's office, or to an urgent care, some kind of medical facility, three times, reliably, at a specified period of time.

但为了保证接种效果,人们必须亲自去诊疗室,或者在急诊室里,使用一些医学设施辅助接种,还需要接种三次,它只在一段时间内有效

耶鲁公开课 - 生物医学工程探索课程节选