Complex sentence: Cooper was born Margaret Elizabeth Douglas in Punta del Este, Uruguay on 25 January 1918, where her Canadian father, Jack Douglas, owned a beach house, across the River Plate from Argentina, where he owned a beef ranch.
Split into simpler sentences: Cooper was born Margaret Elizabeth Douglas in Punta del Este, Uruguay on 25 January 1918. Her father, Jack Douglas, originally from Canada, owned a beach house across the River Plate from Argentina, where he owned a beef ranch.