Complex sentence: Fearing German irredentism, Denmark refused to consider the return of the area without a plebiscite; the two Schleswig Plebiscites took place on 10 February and 14 March 1920, respectively.
Split into simpler sentences: Fearing German irredentism, Denmark refused to consider the return of the area without a plebiscite. The two Schleswig Plebiscites took place on 10 February and 14 March 1920, respectively.