But we know that at 10:31, General Larry Arnold instructed his staff to broadcast the following over a NORAD instant messaging  10:31 Vice president has cleared to us to intercept tracks of interest and shoot them down if they do not respond per [General Arnold].
( But ( we ( ( know ( that ( ( at 10:31 ) ( , ( ( General ( Larry Arnold ) ) ( instructed ( his ( staff ( to ( ( ( ( broadcast ( the following ) ) ( over ( a ( NORAD ( instant messaging ) ) ) ) ) ( ( 10:31 ( Vice president ) ) ( has ( ( cleared ( to us ) ) ( to ( ( ( intercept ( tracks ( of interest ) ) ) and ) ( ( shoot them ) down ) ) ) ) ) ) ) ( if ( they ( ( do not ) ( respond ( per ( -LSB- ( General ( Arnold -RSB- ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (CC But) (NP (PRP we)) (VP (VBP know) (SBAR (IN that) (S (PP (IN at) (NP (CD 10:31))) (, ,) (NP (NNP General) (NNP Larry) (NNP Arnold)) (VP (VBD instructed) (NP (PRP$ his) (NN staff) (S (VP (TO to) (VP (VB broadcast) (NP (DT the) (NN following)) (PP (IN over) (NP (DT a) (JJ NORAD) (JJ instant) (NN messaging))) (SBAR (S (NP (CD 10:31) (NNP Vice) (NN president)) (VP (VBZ has) (VP (VBN cleared) (PP (TO to) (NP (PRP us))) (S (VP (TO to) (VP (VP (VB intercept) (NP (NP (NNS tracks)) (PP (IN of) (NP (NN interest))))) (CC and) (VP (VB shoot) (NP (PRP them)) (PRT (RP down)))))))))) (SBAR (IN if) (S (NP (PRP they)) (VP (VBP do) (RB not) (VP (VB respond) (PP (IN per) (NP (NNP -LSB-) (NNP General) (NNP Arnold) (NNP -RSB-))))))))))))))) (. .)))
General Larry Arnold told his staff to broadcast over a NORAD messaging service at 10:31 that the Vice president had said to hold off on shooting down any hijacked planes until the President could be reached.
( ( General ( Larry Arnold ) ) ( ( told ( his ( staff ( to ( ( ( broadcast over ) ( ( a ( NORAD ( messaging service ) ) ) ( at 10:31 ) ) ) ( that ( ( the ( Vice president ) ) ( had ( ( said ( to ( ( hold off ) ( on ( ( shooting down ) ( any ( hijacked planes ) ) ) ) ) ) ) ( until ( ( the President ) ( could ( be reached ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP General) (NNP Larry) (NNP Arnold)) (VP (VBD told) (NP (PRP$ his) (NN staff) (S (VP (TO to) (VP (VB broadcast) (PRT (RP over)) (NP (NP (DT a) (JJ NORAD) (NN messaging) (NN service)) (PP (IN at) (NP (CD 10:31)))) (SBAR (IN that) (S (NP (DT the) (NNP Vice) (NN president)) (VP (VBD had) (VP (VBN said) (S (VP (TO to) (VP (VB hold) (PRT (RP off)) (PP (IN on) (S (VP (VBG shooting) (PRT (RP down)) (NP (DT any) (JJ hijacked) (NNS planes)))))))) (SBAR (IN until) (S (NP (DT the) (NNP President)) (VP (MD could) (VP (VB be) (VP (VBN reached))))))))))))))) (. .)))