( Therefore ( we ( ( would ( ( ( hybridize ( ( the ( carbon atom ) ) ( in ( ethyne sp ) ) ) ) , ) ( to ( account ( for ( ( ( ( ( the ( C-C ( triple bond ) ) ) ( -LRB- ( ( ( ( one sigma ) plus ) ( two ( pi bonds ) ) ) -RRB- ) ) ) and ) ( the ( single ( C-H bonds ) ) ) ) ( -LRB- ( ( a ( sigma bond ) ) -RRB- ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Therefore)) (NP (PRP we)) (VP (MD would) (VP (VB hybridize) (NP (NP (DT the) (NN carbon) (NN atom)) (PP (IN in) (NP (JJ ethyne) (NN sp)))) (, ,) (S (VP (TO to) (VP (VB account) (PP (IN for) (NP (NP (DT the) (JJ C-C) (JJ triple) (NN bond)) (PRN (-LRB- -LRB-) (NP (NP (CD one) (NN sigma)) (CC plus) (NP (CD two) (NN pi) (NNS bonds))) (-RRB- -RRB-)) (CC and) (NP (DT the) (JJ single) (JJ C-H) (NNS bonds)) (PRN (-LRB- -LRB-) (NP (DT a) (NN sigma) (NN bond)) (-RRB- -RRB-))))))))) (. .)))
Therefore we would hybridize the carbon atom in ethyne sp, to account for the C-C triple bond (one sigma plus two pi bonds) and the single C-H bonds (a sigma 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))))) (. .)))