Sentence Correction (SC) | Re: Construction of the Roman Colosseum, which was officially known as the

Construction of the Roman Colosseum,which was officially known as the Flavian Amphitheater, began in A.D. 69,during the reign of Vespasian , was completed a decadelater, during the reign of Titus, who opened the Colosseum with a one-hundred-day cycle of religious pageants, gladiatorial games, and spectacles.

If we ignore the fluff, the flaw becomes apparent. The original sentence ismissing a conjunction before the clause 'was completed a decade later . The sentence hides this flaw very well
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