( ( The image ) ( ( is ( ( formed ( by ( ( the refraction ) ( of light ) ) ) ) ( through ( the lens ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN image)) (VP (VBZ is) (VP (VBN formed) (PP (IN by) (NP (NP (DT the) (NN refraction)) (PP (IN of) (NP (NN light))))) (PP (IN through) (NP (DT the) (NN lens))))) (. .)))
The image is formed by the refraction of light through the lens.
(ROOT (S (NP (DT An) (NN image)) (VP (VBZ is) (NP (NP (DT a) (NN copy)) (PP (IN of) (NP (NP (DT an) (NN image)) (VP (VBN formed) (PP (IN by) (NP (NN reflection) (CC or) (NN refraction)))))))) (. .)))