( There ( ( are ( ( two types ) ( of ( steps ( on ( the surface ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (NP (NNS steps)) (PP (IN on) (NP (DT the) (NN surface))))))) (. .)))
There are two types of steps on the surface.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS types)) (PP (IN of) (NP (NN surface) (NNS waves))))) (. .)))