Complex sentence: The Three Towns is the term often used to refer to the neighbouring Devon, England towns of Plymouth, Devonport and East Stonehouse, which were formally merged in 1914 to become the Borough of Plymouth.
Split into simpler sentences: The Three Towns is the term often used to refer to the neighbouring towns of Plymouth, Devonport and East Stonehouse in the county of Devon, England. They were formally merged in 1914 to become the Borough of Plymouth.