( ( Mammal ears ) ( ( are ( relatively ( ( complex ( , ( ( ( the ( middle ear ) ) ( containing ( three bones ) ) ) , ) ) ) ( as ( opposed ( to ( ( only ( one bone ) ) ( in ( ( the ( middle ear ) ) ( of ( ( reptiles and ) birds ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Mammal) (NNS ears)) (VP (VBP are) (ADJP (RB relatively) (JJ complex) (PRN (, ,) (S (NP (DT the) (JJ middle) (NN ear)) (VP (VBG containing) (NP (CD three) (NNS bones)))) (, ,)) (SBAR (IN as) (S (VP (VBN opposed) (PP (TO to) (NP (NP (RB only) (CD one) (NN bone)) (PP (IN in) (NP (NP (DT the) (JJ middle) (NN ear)) (PP (IN of) (NP (NNS reptiles) (CC and) (NNS birds)))))))))))) (. .)))
Mammal ears are relatively complex, the middle ear containing three bones, as opposed to only one bone in the middle ear of reptiles and birds.
(ROOT (S (NP (DT The) (JJ mammalian) (JJ middle) (NN ear)) (VP (VBZ has) (NP (CD three) (NNS bones))) (. .)))