You never call.
( You ( never ( call . ) ) )
(ROOT (S (NP (PRP You)) (ADVP (RB never)) (VP (VBP call)) (. .)))
You often call. 
( You ( often ( call . ) ) )
(ROOT (S (NP (PRP You)) (ADVP (RB often)) (VP (VBP call)) (. .)))