______ morphemes are those that cannot be used independently but

______ morphemes are those that cannot be used independently but have to be combined with other morphemes, either free or bound, to form a word.
A、Free
B、Bound
C、Root
D、Affix
【正确答案】：B
【题目解析】：粘着语素是指不能单独使用，但必须与其他语素结合(自由语素或粘着语素)才能构成一个单词的语素。