( ( ( ( knee-jerk reflex ) , ) ( Achilles ( tendon ( reflex -RRB- ) ) ) ) . )
(ROOT (NP (NP (JJ knee-jerk) (NNS reflex)) (, ,) (NP (NNP Achilles) (NNP tendon) (NNP reflex) (-RRB- -RRB-)) (. .)))
knee-jerk reflex, Achilles tendon reflex).
(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))))))))))))