( ( ( Heat Engine ) ( ( A ( heat engine ) ) ( is ( ( a machine ) ( that ( ( ( ( extracts heat ) ( from ( the environment ) ) ) and ) produces ) ) ) ) ) ) ( ( ( ( work , ) typically ) ( in ( ( the form ) ( of ( mechanical ( or ( electrical energy ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Heat) (NNP Engine)) (SBAR (S (NP (DT A) (NN heat) (NN engine)) (VP (VBZ is) (NP (NP (DT a) (NN machine)) (SBAR (WHNP (WDT that)) (S (VP (VP (VBZ extracts) (NP (NN heat)) (PP (IN from) (NP (DT the) (NN environment)))) (CC and) (VP (VBZ produces)))))))))) (VP (VBP work) (, ,) (ADVP (RB typically)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (JJ mechanical) (CC or) (JJ electrical) (NN energy)))))) (. .)))
Heat Engine A heat engine is a machine that extracts heat from the environment and produces work, typically in the form of mechanical or electrical energy.
(ROOT (S (NP (NNP Heat)) (VP (VBZ is) (VP (VBN produced) (SBAR (WHADVP (WRB when)) (S (NP (NN paper)) (VP (VBZ is) (VP (VBN burned))))))) (. .)))
Heat is produced when paper is burned.