( ( If ( symptoms appear ) ) ( , ( they ( ( are ( divided ( into ( three stages ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (NNS symptoms)) (VP (VBP appear)))) (, ,) (NP (PRP they)) (VP (VBP are) (VP (VBN divided) (PP (IN into) (NP (CD three) (NNS stages))))) (. .)))
If symptoms appear, they are divided into three stages.
(ROOT (S (NP (NNP Adulthood)) (VP (VBZ is) (VP (VBN divided) (PP (IN into) (NP (CD three) (NNS stages))))) (. .)))