( ( While ( ( soft corals ) ( also ( grow ( in colonies ) ) ) ) ) ( , ( they ( ( ( do not ) ( ( form reefs ) ( like ( hard coral ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN While) (S (NP (JJ soft) (NNS corals)) (ADVP (RB also)) (VP (VBP grow) (PP (IN in) (NP (NNS colonies)))))) (, ,) (NP (PRP they)) (VP (VBP do) (RB not) (VP (VB form) (NP (NNS reefs)) (PP (IN like) (NP (JJ hard) (NN coral))))) (. .)))
While soft corals also grow in colonies, they do not form reefs like hard coral.
(ROOT (S (NP (NNS Corals)) (VP (VBP build) (NP (NP (JJ hard) (NNS exoskeletons)) (SBAR (WHNP (WDT that)) (S (VP (VBP grow) (S (VP (TO to) (VP (VB become) (NP (NN coral) (NNS reefs)))))))))) (. .)))