Complex sentence: It also controls to a different degree at various times during the course of its eternal war with Eurasia and Eastasia: polar regions, the islands of the Pacific, Antartic regions; it occasionally conquers the rest of Africa, but is later driven back by Eurasia.
Split into simpler sentences: It also controls--to different degrees at various times during the course of its eternal war with Eurasia and Eastasia--polar regions, the islands of the Pacific, and Antartic regions. It occasionally conquers the rest of Africa, but is later driven back by Eurasia.