We first turn to the problem of forecasting sales in retail stores.
( We ( first ( ( ( turn ( to ( ( the problem ) ( of ( forecasting sales ) ) ) ) ) ( in ( retail stores ) ) ) . ) ) )
(ROOT (S (NP (PRP We)) (ADVP (RB first)) (VP (VBP turn) (PP (TO to) (NP (NP (DT the) (NN problem)) (PP (IN of) (NP (NN forecasting) (NNS sales))))) (PP (IN in) (NP (JJ retail) (NNS stores)))) (. .)))
The first issue to look at is sales forecasting.
( ( The ( first ( issue ( to ( look at ) ) ) ) ) ( ( is ( sales forecasting ) ) . ) )
(ROOT (S (NP (DT The) (JJ first) (NN issue) (S (VP (TO to) (VP (VB look) (PP (IN at)))))) (VP (VBZ is) (NP (NP (NNS sales)) (VP (VBG forecasting)))) (. .)))