hi, there! First of all, I'd say your understanding is correct. These are not sentences, but phrases, cuz they are not entire. this pattern is very common in any kinds of languages, in English, it's called 'adjective clause'. Usually people use an adjective to describe a noun, right? for example, a beautiful girl. in many cases though, we can use ' a girl who is beautiful ' instead. the meanings are the same, yet the second pattern is not an adjective, but a complicated phrase/clasue 'who is beautiful' to describe the girl. and now, let's try to compare this pattern with that in Korean, will make sense to you: 내일 이책을 읽을께요. = tomorrow i will read this book. (this is an entire sentence, originally ) 내일 읽을 책 = the book that i will read tomorrow (did you notice the 'book' comes to the head place in English? 'book' is the keyword here, people try to emphasize 'book', instead ' i will read tomorrow', 'what kind of book? the one that i will read tomorrow'. ) therefore, similarly, 내일 읽을 책 is used when you emphasize the certain book that i will read tomorrow. however, unlike English, the nouns come to the head of the clause; in korean , we use (ㅡ)ㄴ/은/는 pattern, to emphasize the keyword. hence many Korean song lyrics use this pattern to emphasize the nouns as well as to make rhythm, or say more poetic and beautiful, especially it's very common in rap lyrics. in daily life, native speakers use this pattern a lot too, when it comes to emphasize some objects, items etc. for example, ' do you like that film?' " which one" " the one you saw yesterday." =" 어제 봤던 영화.' Hope this makes sense to you!!!