Translation:The book is expensive.
Answered "book is expensive" for a quick answer, and they marked me wrong.....
Is it that living things have 가 at the end and nonliving things have 이 at the end of these kinds ofvsentences or what
No, it depends only of padchim. If there is padchim ~이, if no ~가 책 > 책이 친구 > 친구가