But the conflict did not begin on 9/11.
( But ( ( the conflict ) ( ( ( did not ) ( begin ( on 9/11 ) ) ) . ) ) )
(ROOT (S (CC But) (NP (DT the) (NN conflict)) (VP (VBD did) (RB not) (VP (VB begin) (PP (IN on) (NP (CD 9/11))))) (. .)))
The conflict started long before 9/11.
( ( The conflict ) ( ( ( started long ) ( before 9/11 ) ) . ) )
(ROOT (S (NP (DT The) (NN conflict)) (VP (VBD started) (ADVP (RB long)) (PP (IN before) (NP (CD 9/11)))) (. .)))