( ( Behind ( the propeller ) ) ( ( is ( ( ( ( ( ( the rudder ) , ) ( used ( for steering ) ) ) , ) and ) ( the ( water ( pick-up tube ) ) ) ) ) . ) )
(ROOT (SINV (PP (IN Behind) (NP (DT the) (NN propeller))) (VP (VBZ is)) (NP (NP (NP (DT the) (NN rudder)) (, ,) (VP (VBN used) (PP (IN for) (NP (NN steering)))) (, ,)) (CC and) (NP (DT the) (NN water) (NN pick-up) (NN tube))) (. .)))
Behind the propeller is the rudder, used for steering, and the water pick-up tube.
(ROOT (S (NP (NN Fish)) (VP (VBP use) (NP (NP (DT some)) (PP (IN of) (NP (PRP$ their) (NNS fins) (S (VP (TO to) (VP (VB propel) (NP (PRP themselves)) (PP (IN through) (NP (NP (DT the) (NN water)) (CC and) (NP (NP (DT some)) (PP (IN of) (NP (PRP$ their) (NNS fins) (S (VP (TO to) (VP (VB steer)))))))))))))))) (. .)))