( Brass ( is ( ( an alloy ) ( of ( ( copper and ) zinc ) ) ) ) )
(ROOT (S (NP (NNS Brass)) (VP (VBZ is) (NP (NP (DT an) (NN alloy)) (PP (IN of) (NP (NN copper) (CC and) (NN zinc)))))))
Brass is an alloy of copper and zinc
(ROOT (S (NP (NNP Brass) (NNP alloy)) (VP (VBZ is) (VP (VBN made) (PP (IN from) (NP (NN copper) (CC and) (NN zinc))))) (. .)))