【正确答案】：
BOUND MORPHEMES CANNOT OCCUR AS SEPARATE WORDS. THEY ARE BOUND TO OTHER MORPHEME OR MORPHEMES TO FORM WORDS. BOUND MORPHEMES INCLUDE TWO TYPES: BOUND ROOT( THE PART OF THE WORD THAT CARRIES THE FUNDAMENTAL MEANING AND HAS TO COMBINE WITH OTHER MORPHEMES TO MAKE WORDS) AND AFFIX ( FORMS THAT ATTACH TO WORDS OR WORD ELEMENTS TO MODIFY MEANING OR FUNCTION).
【题目解析】：粘附词素是不能作为单独的词出现的词素。它们与其他语素或语素结合形成单词。粘附词素包括两种类型：粘附词根（单词中含有基本意义的部分，必须与其他词素结合才能构成单词）和词缀（附加到单词或单词元素上以改变意义或功能的形式）。