Complex sentence: Helen Elizabeth Clark, ONZ (born 26 February 1950) was the 37th Prime Minister of New Zealand serving three consecutive terms from 1999 to 2008, making her the fifth longest serving person to hold that office.
Split into simpler sentences: Helen Elizabeth Clark, ONZ (born 26 February 1950) was the 37th Prime Minister of New Zealand serving three consecutive terms from 1999 to 2008. As Prime Minister from 1999 to 2008, she is the fifth longest serving person to hold that office.