( ( In ( a ( human cell ) ) ) ( there ( ( are ( ( 23 pairs ) ( of chromosomes ) ) ) . ) ) )
(ROOT (S (PP (IN In) (NP (DT a) (JJ human) (NN cell))) (NP (EX there)) (VP (VBP are) (NP (NP (CD 23) (NNS pairs)) (PP (IN of) (NP (NNS chromosomes))))) (. .)))
In a human cell there are 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))))) (. .)))