The President emphasized to us that he had authorized the shootdown of hijacked aircraft.
( ( The President ) ( ( ( emphasized ( to us ) ) ( that ( he ( had ( authorized ( ( the shootdown ) ( of ( hijacked aircraft ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP President)) (VP (VBD emphasized) (PP (TO to) (NP (PRP us))) (SBAR (IN that) (S (NP (PRP he)) (VP (VBD had) (VP (VBN authorized) (NP (NP (DT the) (NN shootdown)) (PP (IN of) (NP (JJ hijacked) (NN aircraft))))))))) (. .)))
A shootdown of the hijacked aircraft was authorized.
( ( ( A shootdown ) ( of ( the ( hijacked aircraft ) ) ) ) ( ( was authorized ) . ) )
(ROOT (S (NP (NP (DT A) (NN shootdown)) (PP (IN of) (NP (DT the) (JJ hijacked) (NN aircraft)))) (VP (VBD was) (VP (VBN authorized))) (. .)))