Two-book set of English textbooks for learning general verbs and question words. - Title: Sirius 21 English Vol. 1 - Number of books: 2-book set - Contents: Grammar explanations of general verbs, question words, etc. - Number of pages: Approximately 150 pages per volume The Sirius, advanced edition, is unused. The cover is slightly creased. The revised edition has writing in two-thirds of the book, and one-third is still unused, so I will include it as a bonus. Thank you for looking.