( ( A ( transform boundary ) ) ( ( is ( where ( two ( plates ( slide ( against ( each other ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ transform) (NN boundary)) (VP (VBZ is) (SBAR (WHADVP (WRB where)) (S (NP (CD two)) (VP (VBZ plates) (NP (NP (NN slide)) (PP (IN against) (NP (DT each) (JJ other)))))))) (. .)))
A transform boundary is where two plates slide against 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)))))))) (. .)))