The controller continued to try to contact United 93, and asked whether the pilot could confirm that he had been hijacked.
( ( The controller ) ( ( ( ( ( continued ( to ( try ( to ( contact ( United 93 ) ) ) ) ) ) , ) and ) ( asked ( whether ( ( the pilot ) ( could ( confirm ( that ( he ( had ( been hijacked ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN controller)) (VP (VP (VBD continued) (S (VP (TO to) (VP (VB try) (S (VP (TO to) (VP (VB contact) (NP (NNP United) (CD 93))))))))) (, ,) (CC and) (VP (VBD asked) (SBAR (IN whether) (S (NP (DT the) (NN pilot)) (VP (MD could) (VP (VB confirm) (SBAR (IN that) (S (NP (PRP he)) (VP (VBD had) (VP (VBN been) (VP (VBN hijacked)))))))))))) (. .)))
United 93 was not contacted by the controller at all.
( ( United 93 ) ( ( ( was not ) ( contacted ( by ( ( the controller ) ( at all ) ) ) ) ) . ) )
(ROOT (S (NP (NNP United) (CD 93)) (VP (VBD was) (RB not) (VP (VBN contacted) (PP (IN by) (NP (NP (DT the) (NN controller)) (ADVP (IN at) (DT all)))))) (. .)))