试一试以3为间隔从100倒数数，或者，倒背字母表。

Try counting backwards from 100 by 3's, or saying the alphabet backwards, etc.

youdao

他们要求病人完成一项中度压力任务：每间隔7个数字来倒数数字。

The patients performed the mildly stressful task of counting backwards in sevens.

youdao

看完照片之后，他们被要求从8211开始倒数，每隔7个数数一次，数完后再看另一个人的照片，他们与此人相识但不相爱，然后再倒数。

After looking at the photos, they were asked to count backward from 8, 211 by 7s, then look at another picture of a person they knew but were not in love with, then count backward again.

youdao

He came up with the relationship that nu bar, which is called wave number --He found the reciprocal.

他也提出了它们与波数的关系，波数是波长的倒数。

麻省理工公开课 - 固态化学导论课程节选

The one thing you want to keep in mind though is that Hertz does not actually mean inverse seconds, it means cycles per second. So, if you're talking about a car going so many meters per second, you can't say it's going meter Hertz, you have to say meters per second.

写成5每秒，或5赫兹,你们要记住的是赫兹,并不等于秒的倒数，它是每秒的循环数，如果你们说,一辆车一秒可以走多少米,你不能说它走了米赫兹。

麻省理工公开课 - 化学原理课程节选