Complex sentence: Shawn O'Sullivan (born August 27,1964 in Toronto, Ontario) was a Canadian boxer, who won the Light Middleweight Silver medal at the 1984 Summer Olympics.
Split into simpler sentences: Shawn O'Sullivan (born August 27,1964 in Toronto, ON) was a Canadian boxer. O'Sullivan won the Light Middleweight Silver medal at the 1984 Summer Olympics.