There are long days without any food or water, followed by multiple days of clear liquids only.

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In one corner of this tent, Paul Breslin, who works at the Monell Institute in Philadelphia, watched over several tables where twins sat sipping clear liquids from cups and making notes.

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Both forms of hydrazine are clear, flammable liquids.

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Check the rules before you fly, but currently, liquids must be carried in 100ml bottles and stored in a clear plastic bag that holds no more than one litre in total.

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The company made it clear that its production mix in the Americas is continuing to shift from natural gas to liquids, its share going from 45% to 51%.

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