This was later determined to have been Flight 77.
( This ( ( ( was later ) ( determined ( to ( have ( been ( Flight 77 ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBD was) (ADVP (RB later)) (VP (VBN determined) (S (VP (TO to) (VP (VB have) (VP (VBN been) (NP (NNP Flight) (CD 77)))))))) (. .)))
This was determined to be Flight 77 much later.
( This ( ( was ( determined ( to ( ( be ( Flight 77 ) ) ( much later ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBD was) (VP (VBN determined) (S (VP (TO to) (VP (VB be) (NP (QP (CD Flight) (CD 77))) (ADVP (RB much) (RB later))))))) (. .)))