改复数 单数形式复数：This is a good doctor I'm an English teacherIt is

改复数 单数形式复数：This is a good doctor I'm an English teacherIt is 英语!单数句改复数!1.He is a boy2.This is his pen3.It's an English bo 变为复数形式It's a knifeHe is an English teacher I'm a student 就换线 英语改复数形式That is a dictionary This is an exercisebook It is a This is an English map 改为复数形式 This is an apple.that is a pen.改复数形式 把句子改为复数形式 This is a boy What is this in English Is that an E 将下列句子由单数变为复数形式或由复数变为单数形式 ：1.This is an eraser . she is a good student.改为复数形式怎么改 Is he an English boy.复数形式 This is an English(改为复数句) this is an eraser 改复数