Complex sentence: In 1975 Vietnam explicitly recognized China's territorial sovereignty over The Spratly archipelago, and before December 1978 the Malaysian published continental shelf map did not include the reefs and waters of the Spratly archipelago in Malaysian territory.
Split into simpler sentences: In 1975 Vietnam explicitly recognized China's territorial sovereignty over The Spratly archipelago. Before December 1978 the Malaysian published continental shelf map did not include the reefs and waters of the Spratly archipelago in Malaysian territory.