—Hi, Lily and Kate, are you classmates?  —Yes, ________.

在英语中单个字母代表一个单词的是­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­____________

—Your bag is very nice.—              .

---Don’t listen to music in class again, Mike.   ---______.

 --- _____ is your mother?   --- She is 30.