( ( After ( ( observing birds ) ( in flight ) ) ) ( , ( Wilbur ( ( developed ( ( a ( key concept ) ) ( that ( ( revolutionized ( the ( control problem ) ) ) ( in flight ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN After) (S (VP (VBG observing) (NP (NNS birds)) (PP (IN in) (NP (NN flight)))))) (, ,) (NP (NNP Wilbur)) (VP (VBD developed) (NP (NP (DT a) (JJ key) (NN concept)) (SBAR (WHNP (WDT that)) (S (VP (VBD revolutionized) (NP (DT the) (NN control) (NN problem)) (PP (IN in) (NP (NN flight)))))))) (. .)))
After observing birds in flight, Wilbur developed a key concept that revolutionized the control problem in flight.
(ROOT (S (ADVP (RB Not) (RB surprisingly)) (, ,) (NP (JJ controlling) (NN flight)) (VP (VBZ is) (NP (NP (DT the) (NN function)) (PP (IN of) (NP (NP (DT the) (ADJP (RBS most) (JJ developed)) (NN part)) (PP (IN of) (NP (NP (DT a) (NN bird) (POS 's)) (NN brain))))))) (. .)))