Complex sentence: Land clearing operations on Go Noi continued into August by which time much of the island had been completely levelled and seeded with herbicides as enemy activity had been reduced to a minimal level it was decided to close the operation.
Split into simpler sentences: Land clearing operations on Go Noi continued into August by which time much of the island had been completely levelled and seeded with herbicides. As enemy activity had been reduced to a minimal level it was decided to close the operation.