It is still the norm for gays and lesbians to lead double lives, revealing their true feelings only to their closest friends.

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According to the McKinsey report, expanding malaria efforts, as it recommends, would double the number of lives saved per dollar spent.

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Varroa damage shortens their lives by double-digit percentage points.

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Josh Mandel lives a double life.

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Eventually Mr Blunkett's public and private lives formed a double helix, making it hard for him to treat the two separately.

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"Prince Harry and Prince William are a double act for the rest of their lives, " the source said.

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Professor Coleman said that an improvement in lives saved of 6% over the standard treatment was about double what was usually seen in cancer trials of new treatments.

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More than half the world's population already lives in cities and the urban population of sub-Saharan Africa is projected to double by 2030.

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