What the element"-es" indicates is third person singular, present tense, the element"-ed" past tense, and "-ing" progressive aspect. Since they are the smallest unit of language and meaningful, they are alse ______ . ()
A、phonemes
B、morphemes
C、allophones
D、phones
【正确答案】：B
【题目解析】：(P49):词素是语言中最小的意义单位。