You and I have done some important work together.
( ( ( You and ) I ) ( ( have ( ( done ( some ( important work ) ) ) together ) ) . ) )
(ROOT (S (NP (PRP You) (CC and) (PRP I)) (VP (VBP have) (VP (VBN done) (NP (DT some) (JJ important) (NN work)) (ADVP (RB together)))) (. .)))
We never worked together.
( We ( never ( ( worked together ) . ) ) )
(ROOT (S (NP (PRP We)) (ADVP (RB never)) (VP (VBD worked) (ADVP (RB together))) (. .)))