He's written a book,the name of which I've forgotten.为什么用of

He's written a book,the name of which I've forgotten.为什么用of he has written a book the name of which i've forgotten中the n 十万火急的英语问题：he has written a book the name of which i have for I remember he's written a book __ I've completely forgotten he has written a Book _____name i have forgotten. I lived in the house ,of which the name I have forgotten.是否真 In the bag he found a piece of paper on which were written s This is the new book from which I’ve learned a lot of knowle She's written hundreds of books but I've only read a few. Which of the following is a girl's name? 16．The book is mine. I’ve written ______ name on _____ cover i have a book,the cover of which is blue.