code: def drop_modifiers(sentence_str):
      
      tdoc = textacy.Doc(sentence_str, lang='en_core_web_lg')
      new_sent = tdoc.text 
      unusual_char = '形'
      for tag in tdoc:
          if tag.dep_.endswith('mod'): 
              # Replace the tag
              new_sent = new_sent[:tag.idx] + unusual_char * len(tag.text) +\
                      new_sent[tag.idx + len(tag.text):]
      new_sent = new_sent.replace(unusual_char, '')
      new_sent = textacy.preprocess.normalize_whitespace(new_sent)
      return new_sent
docs: Given a string, drop the modifiers and return a string 
      without them