试题题干
Fill in each of the following blanks with a word or an expression.
Human languages have such design features as productivity, 
, displacement, arbitrariness, cultural transmission, duality and interchangeability.
参考答案
试题解析
本题考查人类语言的甄别性特征。
人类语言具有以下的甄别性特征：能产性productivity；离散性discreteness；位移性displacement；任意性arbitrariness；文化传播性cultural transmission；双重性duality；互换性interchangeability。这里缺discreteness。