( ( Hookworms ( like ( this one ) ) ) ( ( are ( common ( human parasites ) ) ) . ) )
(ROOT (S (NP (NP (NNS Hookworms)) (PP (IN like) (NP (DT this) (NN one)))) (VP (VBP are) (NP (JJ common) (JJ human) (NNS parasites))) (. .)))
Hookworms like this one are common human parasites.
(ROOT (S (NP (DT A) (NN hookworm)) (VP (VBZ is) (VP (VBN classified) (PP (IN as) (NP (DT a) (NN parasite))))) (. .)))
A hookworm is classified as a parasite.