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))) (. .)))
They all ran and never looked back.
( They ( all ( ( ( ran and ) ( never ( looked back ) ) ) . ) ) )
(ROOT (S (NP (PRP They)) (ADVP (DT all)) (VP (VP (VBD ran)) (CC and) (VP (ADVP (RB never)) (VBD looked) (PRT (RP back)))) (. .)))