Complex sentence: Siem represented Germany at the WGC-World Cup in 2003 and 2004, and in 2006 he was Bernhard Langer's teammate in the first winning German team in the World Cup.
Split into simpler sentences: Siem represented Germany at the WGC-World Cup in 2003,2004, and 2006. In 2006 he was Bernhard Langer's team-mate in the first winning German team in the World Cup.