is a sea of constant smiles and frequent laughter 
(ROOT (VP (VBZ is) (NP (NP (DT a) (NN sea)) (PP (IN of) (NP (NP (JJ constant) (NNS smiles)) (CC and) (NP (JJ frequent) (NN laughter)))))))
(ROOT (VP (VBZ ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NP (JJ ) (NNS )) (CC ) (NP (JJ ) (NN )))))))