the book about ______the boys are talking is very interesting.为什么这里要用which,用that 为什么不行?

He _____(read) a book about history over the weekend Victor bought the book about history yesterday.（用现在完成时态改写）Victor _____ _____ the book about history _____ two days Hello,I've _____ a book about sports from the school library. 她往袋子里装苹果 She ______ the bag _____ apples.前天我读了一本关于植物的书._____ _____ _____ I read a book about piants.是根据中文补英语句子_____ _____ _____ I read a book about piants.是_____ _____ ------- _____ I re _____ ____ the book? The book is on the table. In the afternoon,she _____ a book about music.A.to read B.read C.reads D.reading The penilbox _____ _____ a ruler _____ an English book. This book is talking about the w( ) The book belongs to me .I'm the ____(own)of the books.It will be very _____(help)to read some books about the anmals. You must _____ the book on time The book _____ (interest) me very much. I am busy _____ (read) the book 是about the life of book 还是about the book of life? The book is about the future of _____（科技）.It will _g____ warm at the North Pole in the future.The book is about the future of _____（科技）.It will _g____ warm at the North Pole in the future.We can _s____ some flowers to our mums on Moth what do you think of the book what _____ _____ _____ _____ _____? I _____ _____（有）the book Harry Potter He is so short that he can't reach the book on the shelf.(改为同义句)He is _____ _____ _____ _____ the book on the shelf.He is _____ _____ _____ _____ _____ the book on the shelf. You should read a book about the right want to look after the birds对about the right want to look after the birds提问____ ____ ____I _____?