Is this a book?的复数形式是什么?3Q

this is a book改为复数形式 Is this a book?的复数形式是什么?3Q This is her book的复数形式 改成复数形式．4.This is a book. Is this a book?的复数句 this book is mine的复数形式是什么 There is a book.改为复数形式 Is that a book改为复数形式 This is a book 改为复数句 把下面的句子变为复数形式1.This is my sister2.That is his brother3.what is that4.Ls this your friend5.that isn't a book This book is in that box.（改为复数形式） How much is this English book?(改为复数形式） This is an Enlish book.(改为复数形式) Is this a book 改成复数形式 Those are chairs 改成单数形式 What are these 改成单数形式 写出下列句子的复数形式 ：This is a book That is my parent Yes it is Is that your pencil? it is an eraser的复数形式!helpit is an eraserThis is my pencilIs that a photo of mineShe is our teacherIs this book on the desk 英语句的复数形式What is this?It is a desk.改为复数形式 写出下列单词的复数形式：this,is,brother,parent,sisier,friend,book,key