曾國藩 湘鄉派 姚鼐 桐城派 陽剛陰柔說 陽剛之美 陰柔之美 古文四象 古文美學 古文八訣 雄 直 怪 麗 茹 遠 潔 適 Tseng Kuo-fan Hsiang hsiang school Yao Nai Tung cheng school The theory of masculine and feminine styles The beauty of the masculine style The beauty of the feminine style The four images of classical prose The aesthetics of classical prose The eight keys to classical prose The virile The direct The grotesque The magnificent The indirect The profound The neat The leisurely