( ( The sun ) ( ( is ( ( composed mostly ) ( of ( hydrogen gas ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN sun)) (VP (VBZ is) (VP (VBN composed) (ADVP (RB mostly)) (PP (IN of) (NP (NN hydrogen) (NN gas))))) (. .)))
The sun is composed mostly of hydrogen gas.
(ROOT (S (NP (DT The) (NN sun)) (ADVP (RB mostly)) (VP (VBD made) (PRT (RP up)) (PP (IN of) (NP (DT the) (NN element) (NN hydrogen)))) (. .)))