Complex sentence: In preparation for Expo 67, the island was greatly enlarged and consolidated with several nearby islands, using the earth excavated during the construction of the Montreal metro; the nearby island, Île Notre-Dame, was built from scratch.
Split into simpler sentences: In preparation for Expo 67, the island was greatly enlarged and consolidated with several nearby islands, using earth excavated during the construction of the Montreal metro. The nearby island, Île Notre-Dame, was built from scratch.