I'm a teacher改复数

I'm a teacher改复数 i'm a teacher 改成复数句子 I'm a teacher的复数形式 I'm a man teacher.复数形式 she isn't a teacher改复数 I'm a pupil.（改为复数句） 怎么改? that is a cup i am a teacher she is my friend 都改复数怎么改啊 改复数 单数形式复数：This is a good doctor I'm an English teacherIt is 变为复数形式It's a knifeHe is an English teacher I'm a student 就换线 I am a teacher.(改为复数) 英语句子改复数形式His father is a teacher. He is a man teacher改为复数句怎么改?