Complex sentence: At the 2008 Summer Olympics in Beijing, Gercsak qualified as an individual swimmer for the men's 400 m freestyle, by posting his lifetime best and clearing a FINA B-standard entry time of 3:52.21 from the national championships in Budapest.
Split into simpler sentences: At the 2008 Summer Olympics in Beijing, Gercsak competed as an individual swimmer in the men's 400 m freestyle. Leading up to his second Games, he posted a lifetime best and FINA B-standard entry time of 3:52.21 at the Hungarian National Trials in Budapest.