( ( ( The waves ) ( created ( by ( a ( stringed instrument ) ) ) ) ) ( ( appear ( to ( ( ( oscillate ( in place ) ) , ) ( ( moving ( from crest ) ) ( to ( trough ( in ( an ( up-and-down motion ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS waves)) (VP (VBN created) (PP (IN by) (NP (DT a) (JJ stringed) (NN instrument))))) (VP (VBP appear) (S (VP (TO to) (VP (VB oscillate) (PP (IN in) (NP (NN place))) (, ,) (S (VP (VBG moving) (PP (IN from) (NP (NN crest))) (PP (TO to) (NP (NP (NN trough)) (PP (IN in) (NP (DT an) (JJ up-and-down) (NN motion))))))))))) (. .)))
The waves created by a stringed instrument appear to oscillate in place, moving from crest to trough in an up-and-down motion.
(ROOT (S (PP (IN In) (NP (DT an) (JJ electromagnetic) (NN wave))) (, ,) (NP (DT the) (NNS crests) (CC and) (NNS troughs)) (VP (VBP represent) (S (VP (VBG oscillating) (NP (NNS fields))))) (. .)))