A lot of his books aren't really fiction but scientific essays that he prepared for publication.
( ( ( A lot ) ( of ( his books ) ) ) ( ( ( are n't ) ( really ( ( fiction ( but ( scientific essays ) ) ) ( that ( he ( prepared ( for publication ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (NN lot)) (PP (IN of) (NP (PRP$ his) (NNS books)))) (VP (VBP are) (RB n't) (VP (ADVP (RB really)) (JJ fiction) (PP (CC but) (NP (JJ scientific) (NNS essays))) (SBAR (IN that) (S (NP (PRP he)) (VP (VBN prepared) (PP (IN for) (NP (NN publication)))))))) (. .)))
He didn't actually write very much fiction.
( He ( ( ( ( did n't ) actually ) ( write ( ( very much ) fiction ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD did) (RB n't) (ADVP (RB actually)) (VP (VB write) (NP (ADJP (RB very) (JJ much)) (NN fiction)))) (. .)))