( ( Your ( knee ( jerk reflex ) ) ) ( ( is ( to ( ( stick up ) ( for ( the baby ) ) ) ) ) . ) )
(ROOT (S (NP (PRP$ Your) (NN knee) (NN jerk) (NN reflex)) (VP (VBZ is) (S (VP (TO to) (VP (VB stick) (PRT (RP up)) (PP (IN for) (NP (DT the) (NN baby))))))) (. .)))
Your knee jerk reflex is to stick up for the baby.
(ROOT (X (NP (DT The) (`` ``) (JJ knee-jerk) ('' '') (NN motion)) (SBAR (IN that) (S (NP (NNS people)) (ADVP (RB involuntarily)) (VP (VBP perform) (SBAR (IN after) (S (S (VP (VBG being) (VP (VBN struck) (PP (IN in) (NP (NP (DT the) (NN knee)) (PP (IN in) (NP (DT a) (JJ certain) (NN way)))))))) (VP (VBZ is) (NP (NP (DT an) (NN example)) (PP (IN of) (NP (DT a) (JJ reflex))))))))))))