( ( The ( normal breathing ) ) ( ( is ( ( ( ( ( between 12 ) to ) 18 ) breaths ) ( per minute ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ normal) (NN breathing)) (VP (VBZ is) (NP (NP (QP (IN between) (CD 12) (TO to) (CD 18)) (NNS breaths)) (PP (IN per) (NP (NN minute))))) (. .)))
The normal breathing is between 12 to 18 breaths per minute.
(ROOT (S (NP (NP (DT The) (JJ normal) (NN respiratory) (NN rate)) (PP (IN per) (NP (NP (NN minute)) (PP (IN in) (NP (JJ adult) (NNS humans)))))) (VP (VBZ is) (NP (CD 12-18) (NNS breaths))) (. .)))