Complex sentence: Her longest span for a role is the voice of Nancy Gribble in the animated series "King of the Hill"; for two episodes in Season 11, she temporarily took over the voice of Bobby Hill.
Split into simpler sentences: Her longest span for a role is the voice of Nancy Gribble in the animated series "King of the Hill". In addition, for two episodes in Season 11, she temporarily took over the voice of Bobby Hill.