(S (S (S (BASENP (JJ Special) (NNS vehicles)) (VP (VBD were) (VP (ADVP (RB also)) (VP (VBN used) (S (VP (TO to) (VP (VB enter) (BASENP (DT the) (NN field))))))))) (COMMA ,) (SBAR (WHNP (WDT which)) (S (VP (VP (VBD was) (RB n't)) (ADJP (RB easily) (JJ accessible)))))) (PERIOD .))