( ( Unstable flight ) ( ( ( is possible ) ( only ( if ( ( the brain ) ( is ( ( an ( active part ) ) ( of ( ( the ( flight ( > ( control system ) ) ) ) ( -LRB- ( ( so ( to speak ) ) -RRB- ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Unstable) (NN flight)) (VP (VBZ is) (ADJP (JJ possible)) (SBAR (RB only) (IN if) (S (NP (DT the) (NN brain)) (VP (VBZ is) (NP (NP (DT an) (JJ active) (NN part)) (PP (IN of) (NP (NP (DT the) (NN flight) (CD >) (NN control) (NN system)) (PRN (-LRB- -LRB-) (S (RB so) (VP (TO to) (VP (VB speak)))) (-RRB- -RRB-))))))))) (. .)))
Unstable flight is possible only if the brain is an active part of the flight &gt; control system (so to speak).
(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))))))) (. .)))