Complex sentence: He announced his executive committee on November 12,2012, appointing Duplessis as one of two Projet Montréal representatives, with responsibility for sustainable development, the environment, parks, and green spaces.
Split into simpler sentences: He announced his executive committee on November 12,2012 and appointed Duplessis as one of two representatives of Projet Montréal. She was given responsibility for sustainable development, the environment, parks, and green spaces.