( There ( ( are ( ( six types ) ( of ( simple machines ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD six) (NNS types)) (PP (IN of) (NP (JJ simple) (NNS machines))))) (. .)))
There are six types of simple  machines .
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD six) (NNS types) (NNS types)) (PP (IN of) (NP (JJ simple) (NNS machines))))) (. .)))