The sixth part of this thesis explains the reason of the internal difference level of defensive modality, by the way of comparing the sematic using and the degree of the modality.

• 本文第六部分，通过比较语气副词“并”、“可”、“又”、“才”在话语使用中表义的差别和口气的强弱，对申辩性口气内部强弱层级的成因做出解释。