Complete the following statements with proper words or expressio

Complete the following statements with proper words or expressions according to the course book.​Idioms each are a semantic ( ),  though each consists of more than one word. 
【正确答案】：UNITY
【题目解析】：成语每个都是语义统一的，尽管每个成语都由多个词（不止一个词）组成。