( ( At ( plate boundaries ) ) ( , ( plates ( ( slide ( past ( each other ) ) ) . ) ) ) )
(ROOT (S (PP (IN At) (NP (NN plate) (NNS boundaries))) (, ,) (NP (NNS plates)) (VP (VB slide) (PP (IN past) (NP (DT each) (JJ other)))) (. .)))
At plate boundaries, plates slide past each other.
(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)))))))) (. .)))