我一直以为那本书是你的 如何翻译

I always assume that the book is yours.
I always think that the book belongs to you.

英语：I always think that the book belongs to you. / is yours.
日本语：いつも君の本と思っています。

I have been thinking that book is yours

I always thought that book was your.

I thought that book was yours

I thought the book was yours.