( ( If ( we ( ( ( looked directly ) ( at ( ( the source ) ( of light ) ) ) ) ( -- ( ( the sun ) -- ) ) ) ) ) ( we ( ( would ( be blinded ) ) . ) ) )
(ROOT (S (SBAR (IN If) (S (NP (PRP we)) (VP (VBD looked) (ADVP (RB directly)) (PP (IN at) (NP (NP (DT the) (NN source)) (PP (IN of) (NP (NN light))))) (PRN (: --) (NP (DT the) (NN sun)) (: --))))) (NP (PRP we)) (VP (MD would) (VP (VB be) (VP (VBN blinded)))) (. .)))
If we looked directly at the source of light -- the sun -- we would be blinded.
(ROOT (S (S (VP (VBG Looking) (ADVP (RB directly)) (PP (IN at) (NP (DT the) (NN sun))))) (VP (MD can) (VP (VB cause) (NP (NN blindness)))) (. .)))