( Well ( ( ( ventilated alveoli ) ( -LRB- ( high ( ( ( PO 2 ) ( in ( capillary blood ) ) ) -RRB- ) ) ) ) ( ( ( can not ) ( ( make up ) ( for ( ( the oxygen ) ( not ( transferred ( in ( ( ( the ( underventilated alveoli ) ) ( with ( a ( low ( PO 2 ) ) ) ) ) ( in ( the ( capillary blood ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Well)) (NP (NP (VBN ventilated) (NNS alveoli)) (PRN (-LRB- -LRB-) (ADVP (JJ high)) (NP (NP (NNP PO) (CD 2)) (PP (IN in) (NP (JJ capillary) (NN blood)))) (-RRB- -RRB-))) (VP (MD can) (RB not) (VP (VB make) (PRT (RP up)) (PP (IN for) (NP (NP (DT the) (NN oxygen)) (VP (RB not) (VBN transferred) (PP (IN in) (NP (NP (DT the) (JJ underventilated) (NNS alveoli)) (PP (IN with) (NP (DT a) (JJ low) (NNP PO) (CD 2))) (PP (IN in) (NP (DT the) (JJ capillary) (NN blood)))))))))) (. .)))
Well ventilated alveoli (high PO 2 in capillary blood) cannot make up for the oxygen not transferred in the underventilated alveoli with a low PO 2 in the capillary blood.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (VP (VBN transferred) (PP (IN through) (NP (NNS capillaries))))) (. .)))