In the following question, out of the four alternatives, select the alternative which will improve the bracketed part of the sentence. In case no improvement is needed, select "no improvement".\n\nThey loaded their ships with spices and silks and (returns) with the summer monsoon.

Introduction / Context:
This question focuses on verb tense consistency in a compound sentence. The sentence is “They loaded their ships with spices and silks and (returns) with the summer monsoon.” Your task is to choose the verb form that correctly aligns with the tense used in the first clause and preserves the intended meaning.

Given Data / Assumptions:

• First verb: loaded (simple past).
• Conjunction: and.
• Bracketed verb: returns, which is in simple present.
• Subject: they (same subject for both actions).
• Context: historical or narrative description of trading activity in the past.

Concept / Approach:
When two actions in a sentence share the same subject and happen in the same time frame, we usually keep them in the same tense. Here, “loaded” is in the simple past, indicating completed actions in the past. Therefore, the second verb should also be in simple past: “returned.” Using “returns” in the present tense creates a tense mismatch and is grammatically incorrect in this context.

Step-by-Step Solution:
Step 1: Identify the tense of the first verb: “loaded” is simple past.Step 2: Recognise that both actions (loading the ships and coming back with the monsoon) belong to the same historical period.Step 3: Therefore, the second verb must also be in simple past: “returned.”Step 4: Check option A: “returned” fits the requirement.Step 5: Substitute: “They loaded their ships with spices and silks and returned with the summer monsoon.” The sentence now reads smoothly and correctly.

Verification / Alternative check:
Consider the other options: “return” (simple present or base form) does not match the past narrative; “returning” would require a different structure (for example, “... and returned, returning with the summer monsoon” or “... and, returning with the summer monsoon, they reached home”), which is not offered here; “No improvement” retains “returns,” which clearly clashes with “loaded”; “had returned” suggests a past perfect that usually needs another past reference point, not present here. Therefore, “returned” is the best and most natural choice.

Why Other Options Are Wrong:
Option B: “return” does not show the past tense needed for a completed action in historical narration.

Option C: “returning” would change the sentence structure and is not correct in its current position without further changes.

Option D: Leaving “returns” unchanged leads to tense inconsistency.

Option E: “had returned” suggests an action completed before another past action, but the sentence structure does not support that more complex time relation.

Common Pitfalls:
Many learners focus on individual verbs and forget to check tense agreement within a sentence. In exam questions, a common trick is to keep one verb in the correct tense and slightly alter the other. Always examine the entire sentence and ensure that all verbs describing related past events share the same tense unless there is a good reason to use a different one.

Final Answer:
returned