( ( If ( you ( ( ( ( block ( in ( ( the water ) ( at ( high tide ) ) ) ) ) and ) then ) ( ( ( ( let it ) out ) ( through ( a turbine ) ) ) ( as ( ( the tide ) falls ) ) ) ) ) ) ( , ( you ( ( can ( generate electricity ) ) . ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (PRP you)) (VP (VP (VBP block) (PP (IN in) (NP (NP (DT the) (NN water)) (PP (IN at) (NP (JJ high) (NN tide)))))) (CC and) (ADVP (RB then)) (VP (VBP let) (NP (PRP it)) (PRT (RP out)) (PP (IN through) (NP (DT a) (NN turbine))) (SBAR (IN as) (S (NP (DT the) (NN tide)) (VP (VBZ falls)))))))) (, ,) (NP (PRP you)) (VP (MD can) (VP (VB generate) (NP (NN electricity)))) (. .)))
If you block in the water at high tide and then let it out through a turbine as the tide falls, you can generate electricity.
(ROOT (S (NP (NP (DT A) (NN turbine)) (VP (VBG using) (NP (NP (NNS tides)) (PP (IN in) (NP (DT the) (NN ocean)))))) (VP (MD can) (VP (VB create) (NP (NN electricity) (NN energy)))) (. .)))