This is a practice and exercise book for the University Entrance Common Test Chemistry. I have marked the question numbers, and I have erased them with an eraser. However, I apologize if there are any remaining marks. The name section of the questions is as shown in the photo, so please understand that only those who are okay with this condition should purchase the book, although the content itself is clean. The answer key is unused and in good condition. This is a school-sold product. Please read the profile before purchasing.