( humans ( normally ( ( have ( ( 23 pairs ) ( of chromosomes ) ) ) . ) ) )
(ROOT (S (NP (NNS humans)) (ADVP (RB normally)) (VP (VBP have) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
humans normally have 23 pairs of chromosomes.
(ROOT (S (NP (DT A) (JJ normal) (JJ human) (NN liver) (NN cell)) (VP (VBZ has) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))