( Scientists ( ( have ( discovered ( thousands ( of exoplanets ) ) ) ) . ) )
(ROOT (S (NP (NNS Scientists)) (VP (VBP have) (VP (VBN discovered) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS exoplanets)))))) (. .)))
Scientists have discovered thousands of exoplanets.
(ROOT (S (NP (DT A) (PRN (-LRB- -LRB-) (NP (NN n)) (-RRB- -RRB-)) (NN exoplanet)) (VP (VBZ is) (ADVP (RB often)) (VP (VBN discovered) (SBAR (IN because) (S (NP (PRP it)) (VP (VBZ causes) (NP (DT a) (NN star) (S (VP (VP (TO to) (VP (VB move))) (CC or) (VP (TO to) (VP (VB dim))))))))))) (. .)))