Differentiate hyphens from subordinate clauses

[mikej888]

defoe/papers/article.py has:

@property
def words_string(self):
    """ 
    Return the full text of the article as a string. Remove all hyphens.
    This merges hyphenated word by may cause problems with subordinate
    clauses (The sheep - the really loud one - had just entered my office).
    """
    return ' '.join(self.words).replace(' - ', '')

Investigate if it is possible to differentiate hyphens from subordinate clauses.