In this sentence improvement question, choose the best alternative to replace the underlined part: This book is adopted to the needs of beginners.

Introduction / Context:
This question tests your understanding of the difference between the verbs adopt and adapt and the correct prepositions used with them. In English, these two verbs look similar but have distinct meanings. Confusing them leads to incorrect and sometimes awkward sentences, which exam setters deliberately use for testing.

Given Data / Assumptions:
- Original sentence: This book is adopted to the needs of beginners. - Underlined part: is adopted to. - Options: adapted to, adapted for, adopted for, No improvement. - The sentence aims to say that the book has been made suitable for beginners.

Concept / Approach:
Adapt means to modify or adjust something so that it becomes suitable for a new use, condition, or audience. Adopt means to take up, accept, or start to use something as one's own, such as a policy, a child, or a method. When we say a book has been changed to suit learners, we use adapted to the needs of beginners. Therefore, the correct verb and preposition combination is adapted to.

Step-by-Step Solution:
Step 1: Determine the intended meaning: the book has been adjusted to meet the needs of beginners. Step 2: Choose the verb that means to adjust or modify, which is adapt, not adopt. Step 3: Note that the standard collocation is adapt something to a purpose, a need, or a situation. Step 4: Replace adopted with adapted and retain to: adapted to the needs of beginners. Step 5: Evaluate adapted for, which is also possible but slightly less precise than adapted to the needs of. Step 6: Evaluate adopted for, which keeps the wrong verb and changes the preposition, so it still does not convey the right meaning. Step 7: No improvement cannot be correct because the original verb adopted is wrong in this context.

Verification / Alternative check:
Compare similar sentences: The syllabus was adapted to suit slow learners or We must adapt our methods to changing circumstances. In each case, adapt to is used when something is adjusted to fit specific needs. Adopt, by contrast, appears in sentences like The organisation adopted a new policy. It would be wrong to say the policy was adopted to the needs, because adopt does not express modification to fit needs.

Why Other Options Are Wrong:
Adapted for in option B is grammatically possible, as in adapted for beginners, but the more complete expression adapted to the needs of beginners in option A matches the original sentence structure better. Adopted for in option C uses the wrong verb, since the book is not being taken up but adjusted. No improvement in option D is incorrect because adopted to is not a standard collocation.

Common Pitfalls:
Candidates often confuse adopt and adapt because they differ by only one letter. A useful memory aid is to link adapt with adjust (both start with a), and adopt with accept (both begin with a as well but relate to taking something over). Whenever the sense is to modify for suitability, choose adapt, and use adapt to when referring to needs or conditions.

Final Answer:
The correct improvement is adapted to the needs of beginners.