Complex sentence: He declared that the Ukrainian national movement must choose between Poland and the Soviet Union, opposed Soviet influences over Poland's Ukrainians, and criticized certain Ukrainian organizations that he viewed as too Soviet-dependent or too extremist (e.g. "Prosvita").
Split into simpler sentences: He declared that the Ukrainian national movement must choose between Poland and the Soviet Union. He opposed Soviet influences over Poland's Ukrainians and criticized certain Ukrainian organizations that he viewed as too Soviet-dependent or too extremist (e.g. "Prosvita").