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Is "Listen up" a complete sentence or is it just a fragment?

marked as duplicate by Davo, Andrew Leach Sep 28 '17 at 16:55

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  • It's a complete sentence. – Greg Lee Sep 28 '17 at 16:47
  • It's one word too many. "Listen!" is a sentence which doesn't require "up" to complete it. – David Sep 28 '17 at 21:24