Many who fled have returned.
( ( Many ( who fled ) ) ( ( have returned ) . ) )
(ROOT (S (NP (NP (JJ Many)) (SBAR (WHNP (WP who)) (S (VP (VBD fled))))) (VP (VBP have) (VP (VBN returned))) (. .)))
Lots of then came back when they realized they had nowhere to run to.
( ( Lots ( of then ) ) ( ( ( came back ) ( when ( they ( realized ( they ( ( had nowhere ) ( to ( run to ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNS Lots)) (PP (IN of) (NP (RB then)))) (VP (VBD came) (PRT (RP back)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VBD realized) (SBAR (S (NP (PRP they)) (VP (VBD had) (ADVP (RB nowhere)) (S (VP (TO to) (VP (VB run) (PP (TO to)))))))))))) (. .)))