The word “denaturalization” can be broken down into “de-”, “nature”, “-al”, “-ize”, “-ation”, each having meaning of its own. These minimal meaningful units are known as（ ） .
A、morphemes
B、allomorphs
C、root
D、stem
【正确答案】：A
【题目解析】：考察词素的基本定义。语言中表达意义的最小单位为词素。