Complete the following statement

Complete the following statements with proper words or expressions according to the course book.The vocabulary of a language is in constant change; old items drop out, new items come in, and as the new replace the old, so the internal ( )  of the whole set alter.
【正确答案】：RELATIONS
【题目解析】：题干译文：一门语言的词汇处于持续不断的变化中；旧词被弃废，而新词增加进来，而且随着新词取代旧词，所以整个集合内的内部什么也在发生变化？The vocabulary of a language is in constant change; old items drop out, new items come in, and as the new replace the old,so the internal relations of the whole set alter. 答案为relations。