( ( Based ( on ( ` ( ( Fermat 's ) ( least-time principle ) ) ) ) ) ( , ( ' ( ( a ( light beam ) ) ( ( will ( take ( ( the path ) ( requiring ( ( the ( least amount ) ) ( of ( time ( between ( two points ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (PP (VBN Based) (PP (IN on) (NP (`` `) (NP (NNP Fermat) (POS 's)) (JJ least-time) (NN principle)))) (, ,) ('' ') (NP (DT a) (JJ light) (NN beam)) (VP (MD will) (VP (VB take) (NP (NP (DT the) (NN path)) (VP (VBG requiring) (NP (NP (DT the) (JJS least) (NN amount)) (PP (IN of) (NP (NP (NN time)) (PP (IN between) (NP (CD two) (NNS points)))))))))) (. .)))
Based on 'Fermat's least-time principle,' a light beam will take the path requiring the least amount of time between two points.
(ROOT (S (NP (NP (NNP Fermat) (POS 's)) (NN principle)) (VP (VBZ states) (SBAR (IN that) (S (NP (NN light)) (VP (MD will) (ADVP (RB always)) (VP (VB take) (NP (NP (DT the) (NN path)) (PP (IN of) (NP (NP (DT the) (JJS least) (NN amount)) (PP (IN of) (NP (NN time))))))))))) (. .)))