( ( In humans ) ( , ( we ( ( have ( ( 23 pairs ) ( of chromosomes ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NNS humans))) (, ,) (NP (PRP we)) (VP (VBP have) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
In humans, we have 23 pairs of chromosomes.
(ROOT (S (NP (NNS Humans)) (VP (VBP have) (NP (NP (CD 23) (JJ pairs) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))