( ( imidazoles ( contain ( 2 ( nitrogen atoms ) ) ) ) ( , ( triazoles ( ( contain ( 3 ( nitrogen atoms ) ) ) . ) ) ) )
(ROOT (S (S (NP (NNS imidazoles)) (VP (VBP contain) (NP (CD 2) (NN nitrogen) (NNS atoms)))) (, ,) (NP (NNS triazoles)) (VP (VBP contain) (NP (CD 3) (NN nitrogen) (NNS atoms))) (. .)))
imidazoles contain 2 nitrogen atoms, triazoles contain 3 nitrogen atoms.
(ROOT (S (NP (NNP Water)) (VP (VBZ contains) (NP (CD 3) (NNS atoms))) (. .)))
Water contains 3 atoms.