In her conclusion, the author sounds a cautionary note.

作者在结尾时敲响了警钟。

《牛津词典》

But he added a cautionary note.

但是他以谨慎的语气补充说。

youdao

So here's the obligatory, but important, cautionary note.

所以这里有些必需的，但重要的警示。

youdao

While this is par for the course, it also important to sound a cautionary note.

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But, notwithstanding the justice of that, I would like to sound a cautionary note.

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However, I would assert a cautionary note with regard to the quality of U.S. intelligence here.

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