He picked out the tune on the piano with one finger.

他凭记忆用一个手指在钢琴上慢慢弹出了那支曲子。

《牛津词典》

He studied the keyboard carefully, one finger poised.

他仔细审视着键盘，一根手指摆好了姿势。

《柯林斯英汉双解大词典》

But we are not only tracking one finger, here.

而且我们不只侦测一根手指。

youdao

To keep himself awake as he flew east during the long night, Post tied a piece of string to one finger.

VOA: special.2009.03.18

He was motionless, all but for one finger that moved up and down in front of his face as if he were marking time with it.

他一动也不动，除了一根手指在他的面前上下摆动,好像在用它标记时间。

耶鲁公开课 - 1945年后的美国小说课程节选

It's funny when I e-mail people. I have one finger, you know.

我给别人发电子邮件很可笑。我用一根手指打字，你知道。

现在的孩子好可怕 - SpeakingMax英语口语达人

That does not mean you should keep one finger hovering over the sell button, however.

FORBES: Market Volatility Requires A Sell Strategy

Speaking of swiping downwards, two-finger scrolling happens to be very smooth, but one finger scrolling isn't supported.

ENGADGET: Fusion Garage JooJoo review

Dad said, and put one finger in the air what I now recognized as a Mr. Bones gesture.

NEWYORKER: Mr. Bones