Complex sentence: The Japanese garrison at Hong Kong strongly resisted the raid, using particularly effective anti-aircraft tactics which the Americans had not previously encountered; a US Navy report described the gunfire the aircraft faced as having been "intense to unbelievable".
Split into simpler sentences: The Japanese garrison at Hong Kong strongly resisted the raid, using particularly effective anti-aircraft tactics which the Americans had not previously encountered. A US Navy report described the gunfire the aircraft faced as having been "intense to unbelievable".