Complex sentence: Melissa Breen (born 17 September 1990) is an Australian 100 metres and 200 metres runner, selected to represent Australia at the 2012 Summer Olympics in the 100 metre event.
Split into simpler sentences: Melissa Breen (born 17 September 1990) is an Australian 100 metres and 200 metres runner. She has been selected to represent Australia at the 2012 Summer Olympics in the 100 metre event.