This is called scratching. DJs do this using a turntable.

VOA: special.2009.10.14

I don't believe we'll-- I'll--come close to scratching the surface of what I would enjoy doing, by the time I've died.

我不能相信-,我能推测死时,自己会对什么感兴趣。

耶鲁公开课 - 死亡课程节选

The lever gets them out of the box, but after more and more trials they stopped scratching at the bars, pushing at the ceiling and so on.

杠杆让它们逃出迷笼，但在经历多次尝试之后,它们不再抓栏杆，不再推顶棚。

耶鲁公开课 - 心理学导论课程节选

Abshir Ahmed,52, has lived all his life along a stretch of the desert near the town of Docol, Scratching the bone-dry earth with his bare,calloused feet, Ahmed says the devastation that he and others are experiencing now is worse than anything they have ever been through before.

VOA: standard.2009.10.06