The problems and explanations are in separate booklets. Part I, Basic Sentence Patterns Review, has been completely filled in and used. Part II, Practice Problems - Basic, has been filled in and used up to Question 6. Questions 7 onwards were printed and used, so there are no markings. Part III, Practice Problems - Advanced, was entirely printed and used, so there are no markings. The explanation booklet has markings from pen and highlighter. Please check the photos. Thank you for your understanding and purchase. Thank you for viewing.