However, green tea contains less caffeine than coffee: there are approximately thirty to sixty mg. of caffeine in six - eight ounces of tea, compared to over one-hundred mg. in eight ounces of coffee.

不过绿茶中的咖啡因含量比咖啡少得多：6 ~ 8盎司茶叶中大约含有30 ~ 60 mg的咖啡因，而8盎司的咖啡中含有超过100 mg咖啡因。

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A cup of filter coffee contains about three times as much caffeine as a cup of tea, although dry tea leaves do contain a higher proportion of caffeine by weight than coffee beans.

一杯过滤咖啡含有的咖啡因大约是一杯茶的3倍，尽管从重量上看，干茶叶所含咖啡因的比例确实比咖啡豆高。

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An online coffee firm have invented what they claim is the world's strongest coffee - which contains 200 per cent more caffeine and comes with its own health warning.

一家网上咖啡店发明了一种自称为“全球最提神”的咖啡。这种咖啡里的咖啡因含量比普通咖啡高出200%，出售时甚至贴出“有害身体健康”的警告。

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Coffee contains many biologically active compounds, including caffeine and phenolic acids, that have potent antioxidant activity and can affect glucose metabolism and sex hormone levels.

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Guarana (aka Guaranine): Guarana is a bean from South America that contains roughly twice as much caffeine as coffee beans.

FORBES: Move up http://i.forbesimg.com t Move down

The Monster spokeswoman said that on a per-ounce basis, Monster contains half the caffeine of some cups of coffee.

WSJ: Energy-Drink Makers Face New York Probe