In fresh water lake, trace elements belonging to hard acid exist mainly as free ion.

在淡水湖泊中，属于硬酸的元素主要以游离离子存在。

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Preparations of the herb, including the amount of valerenic acid, vary widely from study to study, making it hard to draw firm conclusions, says Catherine Ulbricht, co-founder of Natural Standard and a pharmacist at Massachusetts General Hospital in Boston.

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But our favorite (simply because it involves acid) data security solution is Ensconce Data Technology's "Dead on Demand" hard drive.

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The price is lactic acid, which can run you down if not flushed out with long easy rides in between the hard ones.

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