is this your book?为什么this前面用is?

Is this your book? This is ( ) book.your|yours 改错：is this book your? Is this your m( )book Is this your book?Yes,it is is this your book?的同义句 This is your book .You must _____ This book is ( )? 填Your还是Yours? Is this your book?的肯定回答 Is this your book ? 变为复数句 1.Bob,is this your Chinese book? _____me,is this your book,Tom?