Avoid exercising within three hours of bedtime.

就寝前三个小时之内不要有体育运动。

youdao

Within three hours, some had recorded a 50% turnout.

不到三个小时，投票率便已达到50%。

youdao

Within three hours he must experience and express a whole exceptional life.

三个小时之内，他必须体验、诠释一个完整的特殊生命。

youdao

And now when I go into a lecture, the nervousness-- because I give myself the permission to be human-- goes away within as little as three hours into the lecture.

现在当我去上课时，紧张感-,因为我准许自己为人-,在课堂进行三小时后会消失。

哈佛公开课 - 幸福课课程节选

The police ombudsman for Northern Ireland reckons to have an investigator at the scene of a shooting within three hours.

ECONOMIST: Second-guessing the police is a hazardous business

New clot-busting drugs allow some stroke patients to make a full recovery if treated within three hours of their attack.

CNN: Bluetooth device to save stroke victims

In 2002 rt-PA was given an EU licence on condition it was used on patients under 80 within three hours of them having an ischaemic stroke.

BBC: Brain