( ( A ( concave lens ) ) ( ( ( can not ) ( project ( an image ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ concave) (NN lens)) (VP (MD can) (RB not) (VP (VB project) (NP (DT an) (NN image)))) (. .)))
A concave lens cannot project an image.
(ROOT (S (NP (JJ Concave) (NNS lenses)) (VP (MD can) (VP (VB correct) (NP (NN myopia)))) (. .)))