Essential English Grammar In Use By Raymond Murphy ((full)) -

Maria began to study the book diligently, working through each unit and completing the exercises. At first, it was tough - she had to review the rules of verb tenses, modals, and clauses, and she struggled to understand the nuances of each. But as she progressed through the book, she started to notice a change.

: A diagnostic tool at the back of the book to help you identify which units you need to study most. Why Learners Love It

Use this if you have a specific problem (e.g., "I never know when to use 'some' vs 'any' ").