( ( ( ( ( ( bonding theories-ionic ) , ) ( covalent ( -LRB- ( ( ( ( valence bond ) and ) ( molecular orbital ) ) -RRB- ) ) ) ) and ) metallic ) ; )
(ROOT (FRAG (ADJP (ADJP (RB bonding) (JJ theories-ionic)) (, ,) (ADJP (ADJP (JJ covalent)) (PRN (-LRB- -LRB-) (NP (NP (JJ valence) (NN bond)) (CC and) (NP (JJ molecular) (NN orbital))) (-RRB- -RRB-))) (CC and) (ADJP (JJ metallic))) (: ;)))
bonding theories-ionic, covalent (valence bond and molecular orbital) and metallic;
(ROOT (S (NP (JJ Metallic) (NNS bonds)) (VP (VBP hold) (PRT (RP together)) (NP (NP (JJ positive) (NN metal) (NNS ions)) (CC and) (NP (PRP$ their) (JJ valence) (NNS electrons)))) (. .)))