( It ( ( takes ( years ( for ( an ( acorn ( to ( grow ( into ( a ( mighty oak ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ takes) (NP (NP (NNS years)) (PP (IN for) (NP (DT an) (NN acorn) (S (VP (TO to) (VP (VB grow) (PP (IN into) (NP (DT a) (JJ mighty) (NN oak)))))))))) (. .)))
It takes years for an acorn to grow into a mighty oak.
(ROOT (S (NP (NP (DT An) (NN acorn)) (VP (VBG growing) (PP (IN into) (NP (DT an) (JJ adult) (NN tree))))) (VP (MD will) (VP (VB take) (NP (DT the) (JJS longest) (NN time)) (S (VP (TO to) (VP (VB observe)))))) (. .)))