Complex sentence: The island is divided between the sovereign state of East Timor on the eastern part and Indonesia, whose West Timor area on the west constitute part of the province of East Nusa Tenggara.
Split into simpler sentences: The island is divided between the sovereign state of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, West Timor, constitutes part of the province of East Nusa Tenggara.