( ( Hydroelectric power ) ( ( was ( ( the ( cheapest energy ) ) ( to ( be generated ) ) ) ) . ) )
(ROOT (S (NP (JJ Hydroelectric) (NN power)) (VP (VBD was) (NP (NP (DT the) (JJS cheapest) (NN energy)) (SBAR (S (VP (TO to) (VP (VB be) (VP (VBN generated)))))))) (. .)))
Hydroelectric power was the cheapest energy to be generated.
(ROOT (S (NP (PRP You)) (VP (MD can) (VP (VB generate) (NP (JJ hydroelectric) (NN power)) (PP (IN with) (NP (NP (DT the) (NN energy)) (VP (VBN found) (PP (IN in) (S (VP (VBG flowing) (NP (NN water)))))))))) (. .)))