( ( ( The energy ) used ) ( ( is ( defined ( by ( ( the power ) ( of ( ( each device ) ( multiplied ( by ( ( the time ) ( ( for which ) ( they ( are used ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN energy)) (VP (VBN used))) (VP (VBZ is) (VP (VBN defined) (PP (IN by) (NP (NP (DT the) (NN power)) (PP (IN of) (NP (NP (DT each) (NN device)) (VP (VBN multiplied) (PP (IN by) (NP (NP (DT the) (NN time)) (SBAR (WHPP (IN for) (WHNP (WDT which))) (S (NP (PRP they)) (VP (VBP are) (VP (VBN used)))))))))))))) (. .)))
The energy used is defined by the power of each device multiplied by the time for which they are used.
(ROOT (S (NP (NP (JJ Electrical) (NN energy)) (VP (VBN consumed))) (VP (MD can) (VP (VB be) (VP (VBN expressed) (PP (IN as) (NP (NP (DT the) (NN product)) (PP (IN of) (NP (NP (NN power)) (VP (VBN multiplied) (PP (IN by) (NP (NN time))))))))))) (. .)))