The document summarizes the key features and contents of an ideal grammar book for teaching tenses to language learners. It would include clear explanations of each tense, common learner errors, and real-world practice activities. Sample pages show explanations of the present perfect tense, typical learner mistakes, and activity ideas to help understand and practice the tense in a meaningful way. The book aims to prepare learners for errors they may encounter and provide engaging exercises beyond typical textbooks.