Complex sentence: Throughout the first three periods, the Browns were 5/7 on third down conversions; they were 0/4 on third down conversions and gained only one first down in the decisive fourth quarter.
Split into simpler sentences: Throughout the first three quarters, the Browns were 5/7 on third down conversions. However, they were 0/4 on third down conversions and gained only one first down in the decisive fourth quarter.