Q: In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.
Article: The Evergreen Teen Book Club invites you to join us and take full advantage of our limited-time introductory offer. If you join our club, you will receive a certificate for 3 free books. These are yours to keep, even if you decide to cancel your membership. However, if you decide to purchase just one book at the regular club price, you will receive a certificate for an additional 3 free selections after your first order is placed. As our member, you can benefit from all of our super sales and our Bonus Program. You accumulate 2 bonus points with each cash purchase of one book. Every 6 bonus points will earn you a certificate for one free book! To join our club, fill in the brief application listing your name, address, and phone number on the postage-paid card at the bottom of this page. Then drop the card in the mail and our present catalogue will be immediately mailed out to you for your 3 free selections! This catalogue offers a wide selection of over 500 books in every issue, including mysteries, adventures, biographies, cookbooks, sports, and many more. Our catalogue also contains interviews with your favorite authors, reviews of newly published novels, and a teen top-ten list for both fiction and nonfiction. Once you are a member, you will receive our catalogue monthly, but you don't need to purchase any selections. We send you only exactly what you order. If you join before June 30th, we will also provide complimentary shipping ,even if you choose to order nothing except your 3 free books. You can build a great book collection! Begin now by taking advantage of this great offer.
Answer: get one free book for a cash purchase of 3 books
A:
If you join the Evergreen Teen Book Club, you can _ .