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))))) (. .)))
9/11 was merely the exclamation point on a tension that had been building for a decade.
( 9/11 ( ( ( was merely ) ( ( the ( exclamation point ) ) ( on ( ( a tension ) ( that ( had ( been ( building ( for ( a decade ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (CD 9/11)) (VP (VBD was) (ADVP (RB merely)) (NP (NP (DT the) (NN exclamation) (NN point)) (PP (IN on) (NP (NP (DT a) (NN tension)) (SBAR (WHNP (WDT that)) (S (VP (VBD had) (VP (VBN been) (VP (VBG building) (PP (IN for) (NP (DT a) (NN decade)))))))))))) (. .)))