But even without them, he would certainly have understood that the attacks on the World Trade Center would already have unfolded, given Flight 93's tardy departure from Newark.
( But ( ( even ( without them ) ) ( , ( he ( ( ( ( ( would certainly ) ( have ( understood ( that ( ( ( the attacks ) ( on ( the ( World ( Trade Center ) ) ) ) ) ( ( would already ) ( have unfolded ) ) ) ) ) ) ) , ) ( given ( ( ( Flight ( 93 's ) ) ( tardy departure ) ) ( from Newark ) ) ) ) . ) ) ) ) )
(ROOT (S (CC But) (PP (RB even) (IN without) (NP (PRP them))) (, ,) (NP (PRP he)) (VP (MD would) (ADVP (RB certainly)) (VP (VB have) (VP (VBN understood) (SBAR (IN that) (S (NP (NP (DT the) (NNS attacks)) (PP (IN on) (NP (DT the) (NNP World) (NNP Trade) (NNP Center)))) (VP (MD would) (ADVP (RB already)) (VP (VB have) (VP (VBD unfolded))))))))) (, ,) (PP (VBN given) (NP (NP (NP (NNP Flight) (CD 93) (POS 's)) (ADJP (JJ tardy)) (NN departure)) (PP (IN from) (NP (NNP Newark))))) (. .)))
With them, he was unaware that the attacks on the World Trade Center had not occurred.
( ( With them ) ( , ( he ( ( ( was unaware ) ( that ( ( ( the attacks ) ( on ( the ( World ( Trade Center ) ) ) ) ) ( ( had not ) occurred ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN With) (NP (PRP them))) (, ,) (NP (PRP he)) (VP (VBD was) (ADJP (JJ unaware)) (SBAR (IN that) (S (NP (NP (DT the) (NNS attacks)) (PP (IN on) (NP (DT the) (NNP World) (NNP Trade) (NNP Center)))) (VP (VBD had) (RB not) (VP (VBN occurred)))))) (. .)))