( ( ( ( ( ( ( Making oxygen ) ( from water ) ) ( ( Most people ) ( ( can only ) ( ( survive ( for ( a ( few minutes ) ) ) ) ( without oxygen ) ) ) ) ) , ) and ) ( ( ( a ( low level ) ) ( of ( oxygen ( in ( the air ) ) ) ) ) ( can ( cause ( a ( person ( to ( feel ( ( ( very tired ) or ) ( even faint ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (VP (VBG Making) (NP (NN oxygen)) (PP (IN from) (NP (NN water))))) (S (NP (JJS Most) (NNS people)) (VP (MD can) (ADVP (RB only)) (VP (VB survive) (PP (IN for) (NP (DT a) (JJ few) (NNS minutes))) (PP (IN without) (NP (NN oxygen)))))) (, ,) (CC and) (S (NP (NP (DT a) (JJ low) (NN level)) (PP (IN of) (NP (NP (NN oxygen)) (PP (IN in) (NP (DT the) (NN air)))))) (VP (MD can) (VP (VB cause) (NP (DT a) (NN person) (S (VP (TO to) (VP (VB feel) (ADJP (ADJP (RB very) (JJ tired)) (CC or) (ADJP (RB even) (JJ faint)))))))))) (. .)))
Making oxygen from water Most people can only survive for a few minutes without oxygen, and a low level of oxygen in the air can cause a person to feel very tired or even faint.
(ROOT (S (NP (JJS Most) (NNS people)) (VP (MD can) (VP (VB survive) (NP (QP (RB only) (DT a) (JJ few)) (NNS days)) (PP (IN without) (NP (NN water))))) (. .)))