( Bronze ( ( is ( ( an alloy ) ( of ( ( ( ( copper ( -LRB- ( ( 90 % ) -RRB- ) ) ) and ) tin ) ( -LRB- ( ( 10 % ) -RRB- ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN Bronze)) (VP (VBZ is) (NP (NP (DT an) (NN alloy)) (PP (IN of) (NP (NP (NN copper)) (PRN (-LRB- -LRB-) (NP (CD 90) (NN %)) (-RRB- -RRB-)) (CC and) (NP (NN tin)) (PRN (-LRB- -LRB-) (NP (CD 10) (NN %)) (-RRB- -RRB-)))))) (. .)))
Bronze is an alloy of copper ( 90% ) and tin ( 10% ).
(ROOT (S (NP (NN Bronze)) (VP (VBZ is) (NP (NP (DT an) (NN alloy)) (PP (IN of) (NP (NN copper) (CC and) (NN tin))))) (. .)))