( ( ( 7446-11-9 ... ) ( Sulfur trioxide ) ) ... )
(ROOT (NP (NP (CD 7446-11-9)) (: ...) (NP (NNP Sulfur) (NNP trioxide)) (: ...)))
7446-11-9.........................Sulfur trioxide....................................
(ROOT (S (NP (NNP Sulfur)) (VP (MD can) (VP (VB combine) (PP (IN with) (NP (NN oxygen))) (S (VP (TO to) (VP (VB produce) (NP (NN sulfur) (NN trioxide))))))) (. .)))