"next thing one knows" meaning in English

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  "lang_code": "en",
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      "examples": [
        {
          "ref": "1990 July 22, “2 Roofers Hit by Lightning, Man Critically Injured”, in South Florida Sun - Sentinel",
          "text": "([Milton Dosantos]) just said they were on the roof and the next thing they knew, they were flat on their backs",
          "type": "quotation"
        },
        {
          "ref": "1998, Al Rapaport, Buddhism in America",
          "text": "He had three fingers on one hand because one of them had been shot off, and he'd sit there doing this and next thing you know, out would come this three-dimensional folded cage or a box or cranes or snails. Really remarkable.",
          "type": "quotation"
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          "ref": "2007 September 28, Graham Linehan, The IT Crowd, Season 2, Episode 6",
          "text": "Roy: You remember the woman from last night? She seemed lovely, right?\nMoss: She was a delight.\nRoy: Yeah. We get outside, there's a group of tramps, two of whom she knows by name. She starts screaming at them, \"You owe me money! You owe me money!\" She thinks that the tramps owe her money. Next thing I know, it all kicks off. I'm running for my life. It was a horrible evening, a really horrible evening, and she's a really horrible woman.\nMoss: Right. But you slept with her?\nRoy: Yeah."
        }
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      "glosses": [
        "suddenly, out of the blue."
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          "out of the blue",
          "out of the blue"
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        "(idiomatic, colloquial) suddenly, out of the blue."
      ],
      "related": [
        {
          "word": "little did one know"
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      "synonyms": [
        {
          "word": "the next thing one knows"
        }
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        "colloquial",
        "idiomatic"
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    {
      "word": "little did one know"
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        {
          "ref": "1990 July 22, “2 Roofers Hit by Lightning, Man Critically Injured”, in South Florida Sun - Sentinel",
          "text": "([Milton Dosantos]) just said they were on the roof and the next thing they knew, they were flat on their backs",
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          "ref": "1998, Al Rapaport, Buddhism in America",
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          "ref": "2007 September 28, Graham Linehan, The IT Crowd, Season 2, Episode 6",
          "text": "Roy: You remember the woman from last night? She seemed lovely, right?\nMoss: She was a delight.\nRoy: Yeah. We get outside, there's a group of tramps, two of whom she knows by name. She starts screaming at them, \"You owe me money! You owe me money!\" She thinks that the tramps owe her money. Next thing I know, it all kicks off. I'm running for my life. It was a horrible evening, a really horrible evening, and she's a really horrible woman.\nMoss: Right. But you slept with her?\nRoy: Yeah."
        }
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        "suddenly, out of the blue."
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        "(idiomatic, colloquial) suddenly, out of the blue."
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