( ( ( Not so ) ( for bronze ) ) ( , ( ( ( an alloy ) ( of ( ( copper and ) tin ) ) ) . ) ) )
(ROOT (X (ADVP (ADVP (RB Not) (RB so)) (PP (IN for) (NP (NN bronze)))) (, ,) (NP (NP (DT an) (NN alloy)) (PP (IN of) (NP (NN copper) (CC and) (NN tin)))) (. .)))
Not so for bronze, an alloy of copper and tin.
(ROOT (S (NP (NN Bronze)) (VP (VBZ is) (NP (NP (DT an) (NN alloy)) (PP (IN of) (NP (NN copper) (CC and) (NN tin))))) (. .)))