We have heard, seen this pattern before.
( We ( ( have ( ( ( ( heard , ) seen ) ( this pattern ) ) before ) ) . ) )
(ROOT (S (NP (PRP We)) (VP (VBP have) (VP (VBN heard) (, ,) (VBN seen) (NP (DT this) (NN pattern)) (PP (IN before)))) (. .)))
It appeared many times of the last ten years.
( It ( ( appeared ( ( many times ) ( of ( the ( last ( ten years ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD appeared) (NP (NP (QP (JJ many) (NNS times))) (PP (IN of) (NP (DT the) (JJ last) (CD ten) (NNS years))))) (. .)))