( Galileo ( ( ( risks blindness ) ( by ( ( looking ( at ( the sun ) ) ) ( directly ( through ( his telescope ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Galileo)) (VP (VBZ risks) (NP (NN blindness)) (PP (IN by) (S (VP (VBG looking) (PP (IN at) (NP (DT the) (NN sun))) (PP (ADVP (RB directly)) (IN through) (NP (PRP$ his) (NN telescope))))))) (. .)))
Galileo risks blindness by looking at the sun directly through his telescope.
(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)))) (. .)))