【正确答案】：
MORPHEMES ARE ABSTRACT UNITS, WHICH ARE REALIZED IN SPEECH BY DISCRETE UNITS KNOWN AS MORPHS.
【题目解析】：词素是抽象的单位，在语音中由称为形素的离散单位实现。
MORPHEMES ARE ABSTRACT UNITS, WHICH ARE REALIZED IN SPEECH BY DISCRETE UNITS KNOWN AS MORPHS.