( It ( ( is ( made ( by ( ( dissolving ( sulfur trioxide ) ) ( in ( sulfuric acid ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (VP (VBN made) (PP (IN by) (S (VP (VBG dissolving) (NP (NN sulfur) (NN trioxide)) (PP (IN in) (NP (JJ sulfuric) (NN acid)))))))) (. .)))
It is made by dissolving sulfur trioxide in sulfuric acid.
(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))))))) (. .)))