( This ( ( is ( ( ( only optical ) or ) ( visible light ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (RB only) (JJ optical)) (CC or) (NP (JJ visible) (NN light)))) (. .)))
This is only optical or visible light.
(ROOT (S (NP (PRP We)) (VP (VBP call) (NP (DT the) (JJ only) (NN light)) (SBAR (IN that) (S (NP (NNS people)) (VP (MD can) (VP (VB see) (NP (JJ visible) (NN light))))))) (. .)))