( ( ( carbon ( isotope ratio ) ) ( Ratio ( of ( ( ( ( ( ( ( carbon-12 ( to ( either ( of ( the other ) ) ) ) ) , ) ( less common ) ) , ) ( carbon isotopes ) ) , ) ( ( carbon-13 or ) carbon-14 ) ) ) ) ) . )
(ROOT (NP (NP (NN carbon) (NN isotope) (NN ratio)) (NP (NP (NNP Ratio)) (PP (IN of) (NP (NP (ADJP (ADJP (JJ carbon-12) (PP (TO to) (NP (NP (DT either)) (PP (IN of) (NP (DT the) (JJ other)))))) (, ,) (ADJP (RBR less) (JJ common)) (, ,)) (NN carbon) (NNS isotopes)) (, ,) (ADJP (JJ carbon-13) (CC or) (JJ carbon-14))))) (. .)))
carbon isotope ratio Ratio of carbon-12 to either of the other, less common, carbon isotopes, carbon-13 or carbon-14.
(ROOT (S (NP (NP (NNP Carbon) (CD 14) (NN isotope)) (PP (IN of) (NP (NN carbon)))) (VP (VBZ is) (ADVP (RB typically)) (VP (VBN used) (PP (TO to) (NP (NN date) (JJ ancient) (NNS items))))) (. .)))