( ( Common ( sulfonating agents ) ) ( ( are ( ( ( concentrated ( sulfuric acid ) ) , ) ( fuming ( sulfuric ( acid ( , ( sulfur ( trioxide ( and ( other ( sulfur-containing liquids ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Common) (NN sulfonating) (NNS agents)) (VP (VBP are) (VP (VBN concentrated) (NP (JJ sulfuric) (NN acid)) (, ,) (S (VP (VBG fuming) (NP (JJ sulfuric) (NN acid) (, ,) (NN sulfur) (NN trioxide) (CC and) (JJ other) (NN sulfur-containing) (NNS liquids)))))) (. .)))
Common sulfonating agents are concentrated sulfuric acid, fuming sulfuric acid, sulfur trioxide and other sulfur-containing liquids.
(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))))))) (. .)))