Complex sentence: Official American reports say that the "Liberty" was flying her American flag before, during and after the attack; the only exception being a brief period in which one flag had been shot down and then replaced with a larger flag that measured approximately long.
Split into simpler sentences: Official American reports say that the "Liberty" was flying her American flag before, during and after the attack. The only exception being a brief period in which one flag had been shot down and then replaced with a larger flag that measured approximately long.