We shall return to this point later.
( We ( ( shall ( ( return ( to ( this point ) ) ) later ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (MD shall) (VP (VB return) (PP (TO to) (NP (DT this) (NN point))) (ADVP (RB later)))) (. .)))
We will come back to this.  
( We ( ( will ( ( come back ) ( to this ) ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (MD will) (VP (VB come) (PRT (RP back)) (PP (TO to) (NP (DT this))))) (. .)))