The air defense of America began with this call.
( ( ( The ( air defense ) ) ( of America ) ) ( ( began ( with ( this call ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN air) (NN defense)) (PP (IN of) (NP (NNP America)))) (VP (VBD began) (PP (IN with) (NP (DT this) (NN call)))) (. .)))
America's air defense had already begun before the call was made.
( ( ( America 's ) ( air defense ) ) ( ( ( had already ) ( begun ( before ( ( the call ) ( was made ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP America) (POS 's)) (NN air) (NN defense)) (VP (VBD had) (ADVP (RB already)) (VP (VBN begun) (SBAR (IN before) (S (NP (DT the) (NN call)) (VP (VBD was) (VP (VBN made))))))) (. .)))