( ( These ( 3 bones ) ) ( ( work ( as ( ( a ( lever system ) ) ( to ( amplify ( the ( sound vibrations ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT These) (CD 3) (NNS bones)) (VP (VBP work) (SBAR (IN as) (S (NP (DT a) (NN lever) (NN system)) (VP (TO to) (VP (VB amplify) (NP (DT the) (JJ sound) (NNS vibrations))))))) (. .)))
These 3 bones work as a lever system to amplify the sound vibrations.
(ROOT (S (NP (DT The) (JJ long) (NN bone)) (VP (VBP work) (PP (IN as) (NP (NN lever)))) (. .)))