( Atoms ( ( ( are primarily ) ( empty space ) ) . ) )
(ROOT (S (NP (NNS Atoms)) (VP (VBP are) (ADVP (RB primarily)) (NP (JJ empty) (NN space))) (. .)))
Atoms are 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))))) (. .)))