Complex sentence: He also worked as an assistant to James Conlon at the 2004 Spoleto Festival and the 2005 Ravinia Festival and made his house debut at Portland Opera in December 2005 conducting "The Rape of Lucretia".
Split into simpler sentences: He also worked as an assistant to James Conlon at the 2004 Spoleto Festival and the 2005 Ravinia Festival. He made his house debut at Portland Opera in December 2005 conducting "The Rape of Lucretia".