Complex sentence: Opinion polling has been commissioned throughout the duration of the 49th New Zealand Parliament and in the leadup to the 2011 election by various organisations, the main four being Television New Zealand, TV3, the New Zealand Herald and Roy Morgan Research.
Split into simpler sentences: Opinion polling has been commissioned throughout the duration of the 49th New Zealand Parliament and in the leadup to the 2011 election by various organisations. The main four are Television New Zealand, TV3, "The New Zealand Herald" and Roy Morgan Research.