Complex sentence: On August 6,1945, a uranium-based weapon, Little Boy, was detonated above the Japanese city of Hiroshima, and three days later, a plutonium-based weapon, Fat Man, was detonated above the Japanese city of Nagasaki.
Split into simpler sentences: On August 6,1945, a uranium-based weapon, Little Boy, was detonated above the Japanese city of Hiroshima. Three days later, a plutonium-based weapon, Fat Man, was detonated above the Japanese city of Nagasaki.