def break_sentence(sentence, max_sent_len):
    """
  For example, for a sentence with 70 words, supposing the the `max_sent_len'
  is 30, break it into 3 sentences.

  :param sentence: list[str] the sentence
  :param max_sent_len:
  :return:
  """
    ret = []
    cur = 0
    length = len(sentence)
    while cur < length:
        if cur + max_sent_len + 5 >= length:
            ret.append(sentence[cur:length])
            break
        ret.append(sentence[cur:min(length, cur + max_sent_len)])
        cur += max_sent_len
    return ret
