( ( In ( each one ) ) ( , ( ( ( the C ) ( to ( O bond ) ) ) ( ( ( is either ) ( ( ( a ( single bond ) ) or ) ( a ( double bond ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (DT each) (NN one))) (, ,) (NP (NP (DT the) (NNP C)) (PP (TO to) (NP (NNP O) (NN bond)))) (VP (VBZ is) (ADVP (RB either)) (NP (NP (DT a) (JJ single) (NN bond)) (CC or) (NP (DT a) (JJ double) (NN bond)))) (. .)))
In each one, the C to O bond is either a single bond or a double bond.
(ROOT (S (NP (DT A) (JJ double) (NN bond)) (VP (VBZ consists) (PP (IN of) (NP (NP (CD one) (NN sigma) (NN bond)) (CC and) (NP (CD one) (NN pi) (NN bond))))) (. .)))