( ( ( ( ( It ( starts slow ) ) , ) but ) ( ( the pace ) ( quickly changes ) ) ) . )
(ROOT (S (S (NP (PRP It)) (VP (VBZ starts) (ADJP (JJ slow)))) (, ,) (CC but) (S (NP (DT the) (NN pace)) (ADVP (RB quickly)) (VP (VBZ changes))) (. .)))
It starts slow, but the pace quickly changes.
(ROOT (S (NP (NNP Human) (NN evolution)) (VP (VBZ shows) (SBAR (IN that) (S (NP (JJ evolutionary) (NNS changes)) (ADVP (RB typically)) (VP (VBP occur) (PP (IN at) (NP (DT a) (JJ slow) (NN pace))))))) (. .)))