( Ketones ( ( may ( be ( formed ( by ( ( the oxidation ) ( of ( secondary alcohols ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Ketones)) (VP (MD may) (VP (VB be) (VP (VBN formed) (PP (IN by) (NP (NP (DT the) (NN oxidation)) (PP (IN of) (NP (JJ secondary) (NNS alcohols)))))))) (. .)))
Ketones may be formed by the oxidation of secondary alcohols.
(ROOT (S (NP (JJ Secondary) (NN alcohol)) (VP (VBZ forms) (NP (DT a) (NN ketone)) (SBAR (WHADVP (WRB when)) (S (VP (VBD oxidized))))) (. .)))