They are a kind of ______(book).应该填book还是books [关于kind of的用法

They are a kind of ______(book).应该填book还是books [关于kind of的用法 和any kind of books还是any kind of book? Harry Potter is a kind of 用book 还是books? which kind还是kinds of books还是book 5 kinds of book 还是 5 kind of books 还是 5 kinds of books呢 the kind of this book 与a book of this kind 的区别 there ____ a kind of books.是is 还是are? R____ book is a kind of book about cooking 高中英语语法this kind of book/books这种书: +单数谓语动词 a book of this kin 请教“this kind of book”与“this kind of books”区别~ 关于kind of的用法? the kind of book ____ ____and they ______ _____ _____. 这种书很畅