a breath of fresh air now and then 
(ROOT (NP (NP (DT a) (NN breath)) (PP (IN of) (NP (JJ fresh) (NN air))) (ADVP (RB now) (CC and) (RB then))))
(ROOT (NP (NP (DT ) (NN )) (PP (IN ) (NP (JJ ) (NN ))) (ADVP (RB ) (CC ) (RB ))))