Complex sentence: At the end of Second World War the Soviet Union took over territories east of the Oder and Neisse rivers that were part of the Nazi Germany.Some parts of the territory were returned to Poland while the northern part part remained with the Soviet Union.
Split into simpler sentences: At the end of Second World War the Soviet Union took over territories east of the Oder and Neisse rivers that were part of the Nazi Germany. They returned some parts of the territory to Poland while the northern part part remained with the Soviet Union.