Just as a phoneme is the basic unit in the study of phonology, so is a morpheme the basic unit in the study of morphology.
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The smallest meaningful units that can be used freely all by themselves are free morphemes.
A. 对
B. 错
Bound morphemes include two types: roots and affixes.
A. 对
B. 错
Almost every word in every language is composed of one or more morphemes.
A. 对
B. 错
The allomorph is an abstract unit.
A. 对
B. 错
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