( She ( often ( ( ( would n't ) ( drink ( until ( we ( ( arrived ( at ( the ( first ( mountain stream ) ) ) ) ) ( after ( leaving ( a trailhead ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (NP (PRP She)) (ADVP (RB often)) (VP (MD would) (RB n't) (VP (VB drink) (SBAR (IN until) (S (NP (PRP we)) (VP (VBD arrived) (PP (IN at) (NP (DT the) (JJ first) (NN mountain) (NN stream))) (PP (IN after) (S (VP (VBG leaving) (NP (DT a) (NN trailhead)))))))))) (. .)))
She often wouldn't drink until we arrived at the first mountain stream after leaving a trailhead.
(ROOT (S (NP (NNS Streams)) (ADVP (RB often)) (VP (VBP start) (PP (IN in) (NP (NNS mountains)))) (. .)))