The hijacking began between 8:51 and 8:54.
( ( The hijacking ) ( ( began ( between ( ( 8:51 and ) 8:54 ) ) ) . ) )
(ROOT (S (NP (DT The) (NN hijacking)) (VP (VBD began) (PP (IN between) (NP (CD 8:51) (CC and) (CD 8:54)))) (. .)))
Sometime between 8:51 and 8:54 the hijacking was prevented from happening by air marshalls.
( ( Sometime ( between ( ( 8:51 and ) 8:54 ) ) ) ( ( the hijacking ) ( ( was ( prevented ( from ( happening ( by ( air marshalls ) ) ) ) ) ) . ) ) )
(ROOT (S (ADVP (RB Sometime) (PP (IN between) (NP (CD 8:51) (CC and) (CD 8:54)))) (NP (DT the) (NN hijacking)) (VP (VBD was) (VP (VBN prevented) (PP (IN from) (S (VP (VBG happening) (PP (IN by) (NP (NN air) (NNS marshalls)))))))) (. .)))