A word is not the smallest unit

A word is not the smallest unit because many words can be separated even smaller meaningful units. In linguistics, the minimal meaning unit of a language is generally known as（ ）
A、root
B、stem
C、affix
D、morpheme
【正确答案】：D
【题目解析】：一个词不是最小的单位，因为许多词可以被分开甚至更小的有意义的单位。在语言学中，语言的最小意义单位通常被称为词素。