This is the book (which is) lost.为什么which可省略

this is his the best book改错 This book is talking about the w( ) This is the book+that定语从句 This book is famous all over the He is the a_______ of this book WHAT IS THE NAME OF THIS BOOK TOUCHSTONE BOOK怎么样 This is the student's book和 This is the studentThis is the student's book和 This is the student is book 一个概念吗? (1/2)英语语法问题:this is the place which( where ) I have ever visited 用wh this book is the most interesting book this book is the most interesting哪个对?还是都对? 英语翻译this is the book which i bought yesterday.this was the car which the mechanic repaired.he was the man,whom i invited to the party.these were the things which I bought yesterday.He was the man who came here lastweek.He was the policeman wh This book is on the desk不加is This is your book.My is on the desk. This book _________Lucy's book.Her name is on the book cover. This is the first two sections of the book. THIS IS NOT THE END OF THE BOOK怎么样 Whose book is this? This is a book whose is this book?