日韩欧美亚洲 _ 欧美亚洲一区 _ 日本亚洲欧美 _ 亚洲精品欧美 国产白袜脚足J棉袜在线观看_亚洲熟妇av一区二区三区_久久天天躁狠狠躁夜_精品众筹模特私拍在线

填空題

D()is one of the design features of human language which refers to the phenomenon that language consists of two levels: a lower level of meaningless individual sounds and a higher level of meaningful units.

答案: Duality
微信掃碼免費(fèi)搜題