( ( When ( ( a ( future mother ) ) ( is ( infested ( with ( ( roundworms or ) hookworms ) ) ) ) ) ) ( , ( ( most ( of ( the larvae ) ) ) ( ( ( migrate ( to ( the ( small intestine ) ) ) ) ( where ( they ( spend ( their ( adult stage ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (DT a) (JJ future) (NN mother)) (VP (VBZ is) (ADJP (JJ infested) (PP (IN with) (NP (NNS roundworms) (CC or) (NNS hookworms))))))) (, ,) (NP (NP (JJS most)) (PP (IN of) (NP (DT the) (NN larvae)))) (VP (VB migrate) (PP (TO to) (NP (DT the) (JJ small) (NN intestine))) (SBAR (WHADVP (WRB where)) (S (NP (PRP they)) (VP (VBP spend) (NP (PRP$ their) (JJ adult) (NN stage)))))) (. .)))
When a future mother is infested with roundworms or hookworms, most of the larvae migrate to the small intestine where they spend their adult stage.
(ROOT (S (NP (NNS Hookworms)) (VP (VBP infest) (NP (DT the) (NNS intestines))) (. .)))