______ modify the meaning of the stem, but usually do not change

______ modify the meaning of the stem, but usually do not change the part of speech of the original word. ()
A、Prefixes
B、Suffixes
C、Roots
D、Affixes
【正确答案】：A
【题目解析】：(P53):前缀会对词根的意思有所修改,但通常不改变原来单词的词类或词性。