As he sang he kept time on a small drum.

他唱歌时和着一面小鼓的节拍。

《柯林斯英汉双解大词典》

The Maya kept time with a combination of several cycles that meshed together to mark the movement of the sun, moon and Venus.

玛雅人认为时间是由几个循环组成，结合在一起来标记着太阳、月亮和金星的运动。

youdao

The next time you think about going without sleep, consider this: Laboratory animals that are kept awake for long periods of time ...die.

VOA: special.2009.08.26

So in other words, every time I merge the point that I kept emphasizing verbally there and that I'm only touching each number once, means that we have to account for the amount of time it takes to merge N which is going to be just N. Now, this is again one of these cyclical answers.

换言之，之前在做合并时,我不停地强调,对每个数字我只碰了一次，这就是说,我们要记录合并所花的时间量,也就是这里的,这又是一种循环性的答案。

哈佛公开课 - 计算机科学课程节选

This time,however, the calls came from a colony of monkeys kept at the University of Wisconsin.

VOA: special.2009.09.29

Drummers kept time as 20 paddlers in each craft vigorously moved their boats toward the finish line.

CNN: Ancient Chinese sport helps modern breast cancer survivors

He did not demur even when asked to fix watches, although that enterprise did spectacularly badly, and earned him more kicks than kudos, for no watch he took apart ever kept time again.

NEWYORKER: Nawabdin Electrician

American officials maintain that few records were kept at the time, and that many have been lost since.

ECONOMIST: Panama