def extend_wh(lemmas):
    """ ads possible NER targets for wh words"""
    xs = set()
    if 'who' in lemmas:
        xs.update({'person', 'title', 'organization'})
    if 'when' in lemmas:
        xs.update({'time', 'duration', 'date'})
    if 'where' in lemmas:
        xs.update({'location', 'organization', 'city', 'state_or_province',
            'country'})
    if 'how' in lemmas and ('much' in lemmas or 'many' in lemmas):
        xs.update({'money', 'number', 'ordinal'})
    if 'what' in lemmas and 'time' in lemmas:
        xs.update({'time', 'duration', 'date'})
    return xs
