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 also（）.A、phonemesB、morphemesC、allophonesD、phones
题目内容(请给出正确答案)
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 also（）.
