第1个回答 2013-12-16
I'm not sure whose book is this.
或
I'm not sure who the book belong to.
两种都可以的
第2个回答 2013-12-16
I'm not so sure whose book it is.
第3个回答 2013-12-16
I'm not sure whose book this is .
第4个回答 2013-12-16
I don't know whose is this book.
祝你学习进步!!!
第5个回答 2013-12-16
I don't know whose is this book.