Complex sentence: The 19th originally flew antisubmarine missions during World War II, then moved to China in 1944 to begin observation missions in support of Chinese ground forces and later flew resupply missions to resistance forces operating behind enemy lines in French Indochina.
Split into simpler sentences: The 19th originally flew antisubmarine missions during World War II, then moved to China in 1944 to begin observation missions in support of Chinese ground forces. It later flew resupply missions to resistance forces operating behind enemy lines in French Indochina.