( ( ( Two types ) ( of ( bonds ( -- ( ( ( hydrogen and ) covalent ) -- ) ) ) ) ) ( ( occur ( in ( the ( cellulose chain ) ) ) ) . ) )
(ROOT (S (NP (NP (CD Two) (NNS types)) (PP (IN of) (NP (NP (NNS bonds)) (PRN (: --) (NP (NP (NN hydrogen)) (CC and) (NP (NN covalent))) (: --))))) (VP (VBP occur) (PP (IN in) (NP (DT the) (NN cellulose) (NN chain)))) (. .)))
Two types of bonds -- hydrogen and covalent -- occur in the cellulose chain.
(ROOT (S (NP (NN Hydrogen) (NN chloride)) (VP (VBZ is) (NP (DT a) (JJ covalent) (NN compound))) (. .)))