Complex sentence: Throughout 2007 and 2008, Obama helped campaign for her husband's presidential bid, delivering a keynote address at the 2008 Democratic National Convention, and speaking at the 2012 Democratic National Convention.
Split into simpler sentences: Throughout 2007 and 2008, Obama helped campaign for her husband's presidential bid. Obama delivered a keynote address at the 2008 Democratic National Convention, and spoke at the 2012 Democratic National Convention.