Complex sentence: There are many valuable historic relics in Chaozhou city, totally about 600 units and among them 42 are classified as the state, provincial and city's key preservation units of cultural relics.
Split into simpler sentences: There are many valuable historic relics in Chaozhou city, totalling to around 600 units. Among them, 42 are classified under the state, provincial and city's key preservation units of cultural relics.