As the above clues demonstrate, a Graphic CE should be accompanied not only by a flag but also by a Semantic CE.
( ( As ( ( the ( above clues ) ) demonstrate ) ) ( , ( ( a ( Graphic CE ) ) ( ( should ( be ( accompanied ( ( not only ) ( ( ( by ( a flag ) ) ( but also ) ) ( by ( a ( Semantic CE ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN As) (S (NP (DT the) (JJ above) (NNS clues)) (VP (VBP demonstrate)))) (, ,) (NP (DT a) (NNP Graphic) (NNP CE)) (VP (MD should) (VP (VB be) (VP (VBN accompanied) (PP (CONJP (RB not) (JJ only)) (PP (IN by) (NP (DT a) (NN flag))) (CONJP (CC but) (RB also)) (PP (IN by) (NP (DT a) (NNP Semantic) (NNP CE))))))) (. .)))
A graphic CE is a complex form of classification. 
( ( A ( graphic CE ) ) ( ( is ( ( a ( complex form ) ) ( of classification ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ graphic) (NN CE)) (VP (VBZ is) (NP (NP (DT a) (JJ complex) (NN form)) (PP (IN of) (NP (NN classification))))) (. .)))