( ( ( The composition ) ( of air ) ) ( ( is ( ( ( ( ( ( ( ( approximately 21 ) % ) oxygen ) , ) ( ( 78 % ) nitrogen ) ) , ) and ) ( ( 1 % ) argon ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN composition)) (PP (IN of) (NP (NN air)))) (VP (VBZ is) (NP (NP (NP (QP (RB approximately) (CD 21)) (NN %)) (NP (NN oxygen))) (, ,) (NP (ADJP (CD 78) (NN %)) (NN nitrogen)) (, ,) (CC and) (NP (NP (CD 1) (NN %)) (VP (VBN argon))))) (. .)))
The composition of air is approximately 21% oxygen, 78% nitrogen, and 1% argon.
(ROOT (S (NP (NNP Nitrogen) (, ,) (NNP oxygen) (CC and) (NNP argon)) (VP (VBP are) (NP (NP (DT the) (CD three) (JJS most) (JJ common) (NNS elements)) (PP (IN in) (NP (NP (DT the) (NN air)) (SBAR (S (NP (PRP we)) (VP (VB breathe)))))))) (. .)))