( ( Pure carbon ) ( ( can ( be ( ( ( ( ( the ( soft graphite ) ) ( in pencils ) ) , ) or ) ( ( diamond , ) ( the ( hardest element ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Pure) (NN carbon)) (VP (MD can) (VP (VB be) (NP (NP (NP (DT the) (JJ soft) (NN graphite)) (PP (IN in) (NP (NNS pencils)))) (, ,) (CC or) (NP (NP (NN diamond)) (, ,) (NP (DT the) (JJS hardest) (NN element)))))) (. .)))
Pure carbon can be the soft graphite in pencils, or diamond, the hardest element.
(ROOT (S (SBAR (IN Although) (S (NP (PRP they)) (VP (VBP differ) (ADVP (RB vastly)) (PP (IN in) (NP (NNS hardness)))))) (, ,) (NP (NP (NN pencil) (NN lead)) (CC and) (NP (NNS diamonds))) (DT both) (VP (VBP contain) (NP (NN carbon))) (. .)))