( ( ( The heat ) ( from ( the coal ) ) ) ( ( is ( ( used ( to ( boil water ) ) ) ( to ( make ( ( steam , ) ( which ( turns ( ( turbines , ) ( which ( spin ( electrical generators ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN heat)) (PP (IN from) (NP (DT the) (NN coal)))) (VP (VBZ is) (VP (VBN used) (PP (TO to) (NP (NN boil) (NN water))) (S (VP (TO to) (VP (VB make) (NP (NP (NN steam)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ turns) (NP (NP (NNS turbines)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VB spin) (NP (JJ electrical) (NNS generators))))))))))))))) (. .)))
The heat from the coal is used to boil water to make steam, which turns turbines , which spin electrical generators.
(ROOT (S (NP (DT This) (NN heat)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB convert) (NP (NN water)) (PP (IN into) (NP (NP (NN steam)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (ADVP (RB then)) (VP (VBN used) (S (VP (TO to) (VP (VB turn) (NP (DT a) (NN turbine))))))))))) (, ,) (S (ADVP (RB thus)) (VP (VBG generating) (NP (JJ electrical) (NN power))))))))) (. .)))