you're constantly working the same small group of muscles over and over again and

你就一遍又一遍地活动同样的一小组肌肉，然后

健康生活 - SpeakingMax英语口语达人

The medical-device giant Medtronic already has a small group working on a prototype device to see what would be needed to make optogenetics therapy possible.

FORBES: Magazine Article

Network forensics can certainly show what is happening in a small group of people working on a top-secret product.

ECONOMIST: Companies and information

And after a year's discussion within a small working group, it's clear that as yet there is still no agreed definition.

BBC: Whale meeting heads for discord