( Step ( four ( of mitosis ) ) )
(ROOT (S (VP (VB Step) (NP (NP (CD four)) (PP (IN of) (NP (NNS mitosis)))))))
Step four of mitosis
(ROOT (S (NP (NNS Mitosis)) (ADVP (RB actually)) (VP (VBZ occurs) (PP (IN in) (NP (CD four) (NNS phases)))) (. .)))
Mitosis actually occurs in four phases.