( ( ( A ( concave ( rough ( cast-iron tool ) ) ) ) ( in ( which ( ( a ( convex lens ) ) ( is ( ground ( to shape ) ) ) ) ) ) ) . )
(ROOT (NP (NP (DT A) (JJ concave) (JJ rough) (NN cast-iron) (NN tool)) (PP (IN in) (SBAR (WHNP (WDT which)) (S (NP (DT a) (NN convex) (NN lens)) (VP (VBZ is) (ADJP (JJ ground) (S (VP (TO to) (VP (VB shape))))))))) (. .)))
A concave rough cast-iron tool in which a convex lens is ground to shape.
(ROOT (S (NP (NP (DT The) (NN lens)) (PP (IN of) (NP (DT the) (NN eye)))) (VP (VBZ is) (S (NP (DT a) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN convex)) (VP (VB shape)))) (. .)))