( CD ( ( is ( ( working hard ) ( on ( Coral reefs ) ) ) ) . ) )
(ROOT (S (NP (NNP CD)) (VP (VBZ is) (VP (VBG working) (ADVP (RB hard)) (PP (IN on) (NP (NNP Coral) (NNS reefs))))) (. .)))
CD is working hard on Coral reefs .
(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)))))))))) (. .)))