Is that a book on farming?If so,I want to buy ______. (one OR it?)

There is a book that is on the deskThere is a book （that） is on the desk和There is a book on the desk里面的on the desk是不是做定语 Is that a book on farming?If so,I want to buy ______. (one OR it?) This is the best book that there is on the subject可以解释一下这个句子吗,新原题是This is the best book------- on the subject.A.which there is B.that there is C.which is D.what is she said that the book was based on 还是is base on a true storyshe said that the book was based on 还是is based on a true story 说明理由 is there a book on the desk? this is a book on ________(electronic) a book on the table 没有is There is a book on the desk,and ____is an English book A.that B.it到底用that还是it? Is that a book改为复数形式 Is that a book 的同意句. is that a book?作否定回答 Is that a old book改错 whose book is that on the desk同义句 ________ ________the book on the desk? Is that book ______ he borrowed on Friday? 对划线部分提问This is a book（a book）.That is a red book（a red book）. A book is on the desk和On the desk is a book是否一样? That she wrote that book is a story itself The book on the desk is newer than __ in the desk.A.the one B.that答案选哪一个?