( ( The atom ) ( ( ( is primarily ) ( empty space ) ) . ) )
(ROOT (S (NP (DT The) (NN atom)) (VP (VBZ is) (ADVP (RB primarily)) (NP (JJ empty) (NN space))) (. .)))
The atom is primarily empty space.
(ROOT (S (NP (DT The) (NN nucleus)) (VP (VBZ is) (VP (VBN comprised) (ADVP (RB primarily)) (PP (IN of) (NP (JJ empty) (NN space))))) (. .)))