Lesson15-The Riddle of time I. Word study Word list. 1, abuse 6. immune 2. circulation 7. intricate 3. coordinate 8. perception 4, elusive 9. precision 5.gear 10. variable W BTL E BACLesson15—The Riddle of Time W B T L E I. Word Study Word list: 1. abuse 2. circulation 3. coordinate 4. elusive 5. gear 6. immune 7. intricate 8. perception 9. precision 10. variable