Complex sentence: The Seahawks built a ten-point lead to end the third quarter 24-14, and until Super Bowl LI (which also featured the Patriots), no team in Super Bowl history had ever overcome a fourth-quarter deficit of more than seven points.
Split into simpler sentences: The Seahawks built a ten-point lead to end the third quarter 24-14. Previously, no team in Super Bowl history had ever overcome a fourth-quarter deficit of more than seven points.