C
Wikidpedia is unreliable
Website with broken links may be fictional
An article from 2007 may have incorret information from being outdated
She <span>had been working</span> on the project for 2 days before she finished it. So B is the only right one as it's a continuous action before an action with an exact defining past perfect continuous. Also there's a key word "for" that can help us to find out the tense.
Answer:
It doesn´t, taken in account the word <em>long.</em>
Explanation:
It seems to me that the question should be formulated like this:
<em>How does this document etc.</em>
Because the either supporting or expanding of the textbook version can´t be measured in time; you either support it or you expand on it.
