Find the mistakes and write down the correct sentences.
1)European explorers crossed the Atlantic Ocean before the 15th centuty.
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2)They knew a lot about the Atlantic Ocean.
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3)Columbus saw America for the first time on the 10th of October, 1492.
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4)It took him 5 months to cross the Atlantic Ocean.
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5)They had very fast ships.
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6)We ctltbrate Columbus Day on the 14th of October.
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