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)))))))))))) (. .)))
The controller never got a response from the pilot of United 93.
( ( The controller ) ( never ( ( ( got ( a response ) ) ( from ( ( the pilot ) ( of ( United 93 ) ) ) ) ) . ) ) )
(ROOT (S (NP (DT The) (NN controller)) (ADVP (RB never)) (VP (VBD got) (NP (DT a) (NN response)) (PP (IN from) (NP (NP (DT the) (NN pilot)) (PP (IN of) (NP (NNP United) (CD 93)))))) (. .)))