Sentence improvement: The intended sentence is "The battle ______ for some time." Which option gives the correct tense and aspect for the bracketed verb "to rage"?

Introduction / Context:
This question tests your knowledge of verb tense and aspect, especially the past perfect continuous form. The sentence describes a battle that had already been going on for a period before some other past reference point. English often uses "had been" plus an "-ing" verb to express an action that continued up to a moment in the past.

Given Data / Assumptions:
- Base sentence: "The battle (to rage) for some time." - We must replace "to rage" with a correct finite verb form. - No extra context is given, but the phrase "for some time" suggests duration before another event. - Four options use different tenses and voices.

Concept / Approach:
The structure "had been" plus present participle (verb-ing) is the past perfect continuous tense. It is used when an action was in progress for some time before a particular point in the past. A battle can rage, and we describe its continuing nature by saying "had been raging". Forms like "has been raged" are incorrect because "rage" in this sense is an intransitive verb and does not form a natural passive.

Step-by-Step Solution:
Step 1: Recognise that "for some time" points to a continued action of limited duration. Step 2: Decide whether the focus is present or past. Examination sentences with this pattern usually refer to an earlier past period, so past perfect continuous is appropriate. Step 3: Construct "had been raging" from "to rage". Step 4: Compare with option C: "had been raging". This matches exactly. Step 5: Reject "is raging" because it is present continuous and does not match the completed time frame implied by "for some time" in typical narrative past context. Step 6: Reject "has been raged" because it is a passive form with an intransitive verb and is ungrammatical. Step 7: Reject "no improvement" because the bare infinitive "to rage" cannot stand as a main verb in this sentence.

Verification / Alternative check:
Rebuild a full narrative sentence: "The battle had been raging for some time when reinforcements finally arrived." This sounds natural and clearly shows that the battle started earlier and continued up to a second past event. If you use "is raging", it would refer to the present, which conflicts with the expected examination context. Using "has been raged" does not work at all because the battle is not the object of another agent in this sense.

Why Other Options Are Wrong:
Option A, "is raging", places the action in the present and ignores the typical narrative background implied by "for some time". Option B, "has been raged", treats "rage" as a passive verb, which is incorrect because the battle itself is doing the raging. Option D, "no improvement", keeps the infinitive "to rage" and fails to provide a proper finite verb, making the sentence incomplete.

Common Pitfalls:
Many learners confuse "has been" with "had been" and choose present perfect continuous for past situations. A useful rule is that when the time reference is before another past event, past perfect or past perfect continuous is more suitable. Also remember that not all verbs can form passive constructions. Intransitive verbs like "rage", "sleep", or "arrive" usually stay in active forms only.

Final Answer:
The correct improvement is "The battle had been raging for some time."