( ( The pupil ) ( ( allows ( ( ( the ( proper amount ) ) ( of light ) ) ( to ( enter ( ( the inside ) ( of ( the eye ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN pupil)) (VP (VBZ allows) (S (NP (NP (DT the) (JJ proper) (NN amount)) (PP (IN of) (NP (NN light)))) (VP (TO to) (VP (VB enter) (NP (NP (DT the) (NN inside)) (PP (IN of) (NP (DT the) (NN eye)))))))) (. .)))
The pupil allows the proper amount of light to enter the inside of the eye.
(ROOT (S (NP (NP (DT The) (NN pupil)) (PP (IN of) (NP (DT the) (NN eye)))) (VP (VBZ allows) (ADJP (JJ light) (S (VP (TO to) (VP (VB enter)))))) (. .)))
The pupil of the eye allows light to enter.