( ( For example ) ( , ( ( although ( ( elemental sodium ) ( is ( a metal ) ) ) ) ( , ( ( solid ( sodium chloride ) ) ( ( ( ( is ( an insulator ) ) , ) ( ( ( ( ( because ( ( ( the ( valence electron ) ) ( of sodium ) ) ( is ( ( transferred ( to chlorine ) ) ( to ( form ( an ( ionic bond ) ) ) ) ) ) ) ) , ) and ) thus ) ( that ( electron ( ( can not ) ( be ( moved easily ) ) ) ) ) ) ) . ) ) ) ) ) )
(ROOT (S (PP (IN For) (NP (NN example))) (, ,) (SBAR (IN although) (S (NP (JJ elemental) (NN sodium)) (VP (VBZ is) (NP (DT a) (NN metal))))) (, ,) (NP (JJ solid) (NN sodium) (NN chloride)) (VP (VBZ is) (NP (DT an) (NN insulator)) (, ,) (SBAR (SBAR (IN because) (S (NP (NP (DT the) (JJ valence) (NN electron)) (PP (IN of) (NP (NN sodium)))) (VP (VBZ is) (VP (VBN transferred) (PP (TO to) (NP (NN chlorine))) (S (VP (TO to) (VP (VB form) (NP (DT an) (JJ ionic) (NN bond))))))))) (, ,) (CC and) (ADVP (RB thus)) (SBAR (IN that) (S (NP (NN electron)) (VP (MD can) (RB not) (VP (VB be) (VP (VBN moved) (ADVP (RB easily))))))))) (. .)))
For example, although elemental sodium is a metal, solid sodium chloride is an insulator, because the valence electron of sodium is transferred to chlorine to form an ionic bond, and thus that electron cannot be moved easily.
(ROOT (S (NP (NNP Rubber)) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (NP (DT a) (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-) (NNS insulators)) (SBAR (WHNP (WDT that)) (S (VP (VBZ does) (RB not) (VP (VB allow) (S (NP (NNS electrons)) (VP (TO to) (VP (VB move) (PP (IN through) (NP (PRP them)))))))))))))) (. .)))