Complex sentence: He was subsequently named senior correspondent for the Global Television Network's "Global National", but on July 21, before Chin had ever appeared on "Global National", he left the network and joined the communications staff of Ontario Premier Dalton McGuinty.
Split into simpler sentences: He was subsequently named senior correspondent for the Global Television Network's "Global National". On July 21, before Chin had ever appeared on "Global National", he left the network and joined the communications staff of Ontario Premier Dalton McGuinty.