( This ( ( is ( ( the ( only light ) ) ( humans ( can see ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN light)) (SBAR (S (NP (NNS humans)) (VP (MD can) (VP (VB see))))))) (. .)))
This is the only light humans can see.
(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))))))) (. .)))