Complex sentence: Dawn Therese Brancheau (April 16,1969--February 24,2010) was an American SeaWorld trainer who worked with orcas at SeaWorld Orlando, for sixteen years, and was their poster girl, until she was killed by the killer whale known as Tilikum.
Split into simpler sentences: Dawn Therese Brancheau (April 16,1969--February 24,2010) was an American SeaWorld trainer who worked with orcas at SeaWorld Orlando, for sixteen years. She was their poster girl, until she was killed by the killer whale known as Tilikum.