( ( All ( we ( can see ) ) ) ( ( is ( visible light ) ) . ) )
(ROOT (S (NP (NP (DT All)) (SBAR (S (NP (PRP we)) (VP (MD can) (VP (VB see)))))) (VP (VBZ is) (NP (JJ visible) (NN light))) (. .)))
All we can see is 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))))))) (. .)))