Complex sentence: The two teams met again in the 2012 BCS National Championship Game for a rematch, when the Crimson Tide shut out LSU 21--0, with the Tigers not even advancing the ball out of their own half until the 3rd quarter.
Split into simpler sentences: The two teams met again in the 2012 BCS National Championship Game. This time, the Crimson Tide shut out LSU 21--0, with the Tigers not even advancing the ball out of their own half until the 3rd quarter.