( Myelin ( ( is ( like ( ( the insulation ) ( ( ( surrounding and ) protecting ) ( electrical wires ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Myelin)) (VP (VBZ is) (PP (IN like) (S (NP (DT the) (NN insulation)) (VP (VBG surrounding) (CC and) (VBG protecting) (NP (JJ electrical) (NNS wires)))))) (. .)))
Myelin is like the insulation surrounding and protecting electrical wires.
(ROOT (S (NP (JJ Electrical) (NNS wires)) (VP (VBP are) (ADVP (RB usually)) (VP (VBN covered) (PP (IN with) (NP (NN plastic) (CC or) (NN rubber))) (S (VP (TO to) (VP (VB insulate) (NP (DT the) (JJ electrical) (NN wire))))))) (. .)))
Electrical wires are usually covered with plastic or rubber to insulate the electrical wire.