Which of the following is NOT true?（ ）

Which of the following is NOT true?（ ）
A、A word is the smallest free form of a language.
B、A word is a sound unity.
C、A word has a given meaning.
D、A word can be used freely in a sentence.
【正确答案】：A
【题目解析】：The smallest free form of a language is a morpheme. A选项表述不正确。