( ( A ( fuel cell ) ) ( ( will ( ( ( produce energy ) ( in ( ( the form ) ( of ( ( electricity and ) heat ) ) ) ) ) ( ( as long ) ( as ( fuel ( is supplied ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN fuel) (NN cell)) (VP (MD will) (VP (VB produce) (NP (NN energy)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN electricity) (CC and) (NN heat))))) (ADVP (ADVP (RB as) (RB long)) (SBAR (IN as) (S (NP (NN fuel)) (VP (VBZ is) (VP (VBN supplied)))))))) (. .)))
A fuel cell will produce energy in the form of electricity and heat as long as fuel is supplied.
(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.