This is Susan.
( This ( ( is Susan ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NNP Susan))) (. .)))
Susan is a a fifth grade teacher. 
( Susan ( ( is ( a ( a ( fifth ( grade teacher ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Susan)) (VP (VBZ is) (NP (DT a) (DT a) (JJ fifth) (NN grade) (NN teacher))) (. .)))