( But ( ( ( about 8 ) ( per ( ( cent , ) ( including ( migraine ( and ( hangover headaches ) ) ) ) ) ) ) ( ( are ( ( caused ( by ( blood vessels ) ) ) ( in ( ( the brain ) ( ( dilating or ) expanding ) ) ) ) ) . ) ) )
(ROOT (S (CC But) (NP (NP (QP (RB about) (CD 8))) (PP (IN per) (NP (NP (NN cent)) (, ,) (PP (VBG including) (NP (NN migraine) (CC and) (NN hangover) (NNS headaches)))))) (VP (VBP are) (VP (VBN caused) (PP (IN by) (NP (NN blood) (NNS vessels))) (PP (IN in) (NP (NP (DT the) (NN brain)) (VP (VBG dilating) (CC or) (VBG expanding)))))) (. .)))
But about 8 per cent, including migraine and hangover headaches are caused by blood vessels in the brain dilating or expanding.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NP (NN blood) (NNS vessels)) (PP (IN in) (NP (DT the) (NN head)))) (VP (VBP dilate)))) (, ,) (NP (NP (DT a) (NN migraine)) (, ,) (NP (DT a) (JJ severe) (NN headache)) (, ,)) (VP (MD can) (VP (VB occur))) (. .)))