Complex sentence: Bob Altena (born February 11,1986 in Brunssum, Limburg) is a Dutch decathlete, who's greatest achievement was a ninth place at the 2004 World Junior Championships in Athletics.
Split into simpler sentences: Bob Altena (born February 11,1986 in Brussum) is a Dutch decathlete. His greatest achievement was a ninth place at the 2004 World Junior Championships in Athletics.