There was something odd about him but I couldn't put my finger on it.

他有些古怪，但我说不出到底是什么。

《牛津词典》

I cannot put my finger on it now.

我不能把我的手指在这个时候。

youdao

I know the answer, but I cant put my finger on it.

我知道答案，可我说不确切了。

youdao

"I've been trying to put my finger on it for 30 years, " says Wittmann, sounding genuinely bewildered.

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But my wife, as soon as she had Internet capability, she re-ordered the ring and she put it on my finger in my neighbor's yard, the place I lost it.

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"I just put my finger on a map, and it landed on Nebraska, " Borakove said.

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