Marriage is an important institution.
( Marriage ( ( is ( an ( important institution ) ) ) . ) )
(ROOT (S (NP (NNP Marriage)) (VP (VBZ is) (NP (DT an) (JJ important) (NN institution))) (. .)))
Marriage is irrelevant.
( Marriage ( ( is irrelevant ) . ) )
(ROOT (S (NP (NNP Marriage)) (VP (VBZ is) (ADJP (JJ irrelevant))) (. .)))