（ ）does not generally change the word-class of the stem but only

（ ）does not generally change the word-class of the stem but only modifies its meaning.
A、Prefixation
B、Suffixation
C、Affixation
D、Derivation
【正确答案】：A
【题目解析】：词缀的功能前缀多是在词根的含义基础上，改变词汇的含义，如否定前缀im-。