Complex sentence: He held the WBA (Regular) and IBO super-lightweight titles from 2012 to 2014, and an an amateur won a bronze medal in the lightweight division at the 2005 World Championships.
Split into simpler sentences: He held the WBA (Regular) and IBO super-lightweight titles from 2012 to 2014. As an amateur he won a bronze medal in the lightweight division at the 2005 World Championships.