( ( ( Each ( of ( the ( four ( sp 3 ) ) ) ) ) orbitals ) ( ( ( has ( ( an ( unpaired electron ) ) ( explaining ( ( the tetra-valency ) ( for ( such ( an sp ) ) ) ) ) ) ) ( 3 carbon ) ) . ) )
(ROOT (SINV (S (NP (NP (DT Each)) (PP (IN of) (NP (DT the) (CD four) (NN sp) (CD 3)))) (VP (VBZ orbitals))) (VP (VBZ has) (NP (NP (DT an) (JJ unpaired) (NN electron)) (VP (VBG explaining) (NP (NP (DT the) (NN tetra-valency)) (PP (IN for) (NP (PDT such) (DT an) (NN sp))))))) (NP (CD 3) (NN carbon)) (. .)))
Each of the four sp 3 orbitals has an unpaired electron explaining the tetra-valency for such an sp 3 carbon.
(ROOT (S (NP (NNP Carbon)) (VP (VBZ has) (NP (CD four) (JJ valence) (NNS electrons))) (. .)))