Come on, let's have tea. 
( ( Come on ) ( , ( ( let 's ) ( ( have tea ) . ) ) ) )
(ROOT (S (PP (VBN Come) (PP (IN on))) (, ,) (NP (NNP let) (POS 's)) (VP (VBP have) (NP (NN tea))) (. .)))
I wanted a cup of early gray. 
( I ( ( wanted ( ( a cup ) ( of ( early gray ) ) ) ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBD wanted) (NP (NP (DT a) (NN cup)) (PP (IN of) (NP (JJ early) (NNS gray))))) (. .)))