Complex sentence: Joseph Patrick "Joe" Kennedy, Jr. (July 25,1915-August 12,1944) was a Lieutenant who was in the US Navy and died on a secret mission during World War 2.
Split into simpler sentences: Joseph Patrick "Joe" Kennedy, Jr. (July 25,1915-August 12,1944) was a Lieutenant in the US Navy. He died on a secret mission during World War 2.