( Tides ( ( are ( created ( by ( ( the ( gravitational pull ) ) ( of ( the moon ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Tides)) (VP (VBP are) (VP (VBN created) (PP (IN by) (NP (NP (DT the) (JJ gravitational) (NN pull)) (PP (IN of) (NP (DT the) (NN moon))))))) (. .)))
Tides are created by the gravitational pull of the moon.
(ROOT (S (NP (NNP Spring) (NNS tides)) (VP (VBP are) (VP (VBN created) (SBAR (WHADVP (WRB when)) (S (NP (NP (DT the) (NN sun)) (CC and) (NP (NP (NN moon) (POS 's)) (NNS tides))) (VP (VBP match)))))) (. .)))