Complete the following statements with proper words or expressio

Complete the following statements with proper words or expressions according to the course book.According to the positions which affixes occupy in words, affixation falls into two subclasses: ( ) and suffixation.
【正确答案】：PREFIXATION
【题目解析】：According to the positions which affixes occupy in words, affixation falls into two subclasses: prefixation and suffixation. 根据词缀在词中出现的位置，词缀法可分为两类：前缀法和后缀法。