( ( Convergent ( plate boundaries ) ) ( ( exist ( when ( ( two plates ) ( come together ) ) ) ) . ) )
(ROOT (S (NP (JJ Convergent) (NN plate) (NNS boundaries)) (VP (VBP exist) (SBAR (WHADVP (WRB when)) (S (NP (CD two) (NNS plates)) (VP (VBP come) (ADVP (RB together)))))) (. .)))
Convergent plate boundaries exist when two plates come together.
(ROOT (S (NP (DT A) (JJ convergent) (NN plate) (NN boundary)) (VP (VBZ is) (VP (VBN created) (SBAR (WHADVP (WRB when)) (S (NP (CD two) (NNS plates)) (VP (VBP come) (PP (IN toward) (NP (DT each) (JJ other)))))))) (. .)))