Chest pains can be a warning signal of heart problems.

胸部疼痛可能是心脏病的报警信号。

《牛津词典》

E. coli bacteria were modified using BioBrick components to produce a warning signal in the presence of arsenic.

他们利用生物砖组件改变大肠杆菌使其在遇到砷的时候发出警告信号。

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But the move, proponents argued, would boost morale in the colony and send a warning signal to Japan. Churchill conceded.

但是，支持者认为，这会提高该殖民地的士气，向日本发出一个警告信号。丘吉尔让步了。

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Engineers believed the warning signal was wrong and the shield was locked.

VOA: special.2009.06.17

But that whistling past the graveyard ignores the bright flashing warning signal that Romney has reaffirmed.

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Generally, a bearish momentum divergence is a red flag warning signal, which often presages a pullback or correction.

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Until the last two years, that was always a very important warning signal.

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