He thought the biggest barrier was how to change the culture in the ED so that staff would ask screening questions.
( He ( ( thought ( ( the ( biggest barrier ) ) ( was ( how ( to ( ( ( change ( the culture ) ) ( in ( the ED ) ) ) ( so ( that ( staff ( would ( ask ( screening questions ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD thought) (SBAR (S (NP (DT the) (JJS biggest) (NN barrier)) (VP (VBD was) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB change) (NP (DT the) (NN culture)) (PP (IN in) (NP (DT the) (NNP ED))) (SBAR (RB so) (IN that) (S (NP (NN staff)) (VP (MD would) (VP (VB ask) (NP (NN screening) (NNS questions)))))))))))))) (. .)))
The biggest barrier was thought to be how to change the culture, however this wasn't the only barrier which was involved.
( ( ( ( ( ( The ( biggest barrier ) ) ( was ( thought ( to ( be ( how ( to ( change ( the culture ) ) ) ) ) ) ) ) ) , ) however ) ( this ( ( was n't ) ( ( the ( only barrier ) ) ( which ( was involved ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT The) (JJS biggest) (NN barrier)) (VP (VBD was) (VP (VBN thought) (S (VP (TO to) (VP (VB be) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB change) (NP (DT the) (NN culture)))))))))))) (, ,) (ADVP (RB however)) (S (NP (DT this)) (VP (VBD was) (RB n't) (NP (NP (DT the) (JJ only) (NN barrier)) (SBAR (WHNP (WDT which)) (S (VP (VBD was) (VP (VBN involved)))))))) (. .)))