America is under attack.
( America ( ( is ( under attack ) ) . ) )
(ROOT (S (NP (NNP America)) (VP (VBZ is) (PP (IN under) (NP (NN attack)))) (. .)))
Terrorists have attacked America.
( Terrorists ( ( have ( attacked America ) ) . ) )
(ROOT (S (NP (NNS Terrorists)) (VP (VBP have) (VP (VBN attacked) (NP (NNP America)))) (. .)))