Complex sentence: The 2008 IRB Junior World Championship is the first annual international rugby union competition for Under 20 national teams, this competition replaces the now defunct under 19 and under 21 world championships.
Split into simpler sentences: The 2008 IRB Junior World Championship is the first annual international rugby union competition for Under 20 national teams. This competition replaces the now defunct under-19 and under-21 world championships.