this book is mine的复数形式是什么

Is this a book?的复数形式是什么?3Q this is my book. this book is mine 区别是什么? this book is mine. this is my book.写出下列句子的复数形式 this is a book改为复数形式 This book is mine的同义句 what color is the book 的复数形式是什么 this i book is mine How much is this English book?(改为复数形式） This book is in that box.（改为复数形式） 改成复数形式．4.This is a book. This is a book.(改为复数形式）