Переделайте в косвенную речь i think you like reading horror books. why? there are the books of my younger brother.i seldom read this kind of books .i really prefer books on photography and history.

The first person said that he/she thought the second person liked reading horror books.
The second person wanted to know why the first person thought so.
The first person said that there were the books of his/her younger brother and he/she seldom read that kind of books addinf that he/she really prefered books on photography and history.