Alarm bells would not start ringing until these efforts-which could take five minutes or more-were tried and had failed.
( ( Alarm bells ) ( ( ( ( ( would not ) ( ( start ringing ) ( until ( ( these efforts-which ) ( could ( take ( five minutes ) ) ) ) ) ) ) or ) ( more-were ( ( tried and ) ( had failed ) ) ) ) . ) )
(ROOT (S (NP (JJ Alarm) (NNS bells)) (VP (VP (MD would) (RB not) (VP (VB start) (NP (VBG ringing)) (SBAR (IN until) (S (NP (DT these) (NN efforts-which)) (VP (MD could) (VP (VB take) (NP (CD five) (NNS minutes)))))))) (CC or) (VP (ADVP (RB more-were)) (VP (VBD tried)) (CC and) (VP (VBD had) (VP (VBN failed))))) (. .)))
Alarm bells would not start until efforts had failed.
( ( Alarm bells ) ( ( ( would not ) ( start ( until ( efforts ( had failed ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Alarm) (NNS bells)) (VP (MD would) (RB not) (VP (VB start) (SBAR (IN until) (S (NP (NNS efforts)) (VP (VBD had) (VP (VBN failed))))))) (. .)))