(S (S (NP (BASENP (NNS Those)) (SBAR (WHNP (WP who)) (S (VP (VP (VP (VBD did) (RB not)) (VP (VB go))) (SBAR (IN as) (S (VBN instructed))))))) (VP (VBD were) (VP (ADVP (RB usually)) (VP (VP (VBN escorted) (PP (IN by) (NP (BASENP (QP (NN two) (CC or) (NN three)) (NNS guards)) (BASENP (DT each))))) (PP (TO to) (BASENP (DT the) (NNS buses))))))) (PERIOD .))