Improve the bracketed part of the sentence by correcting the auxiliary verb: A beautiful landscape, full of green vegetation, will not just attract our attention but (fill us) with infinite satisfaction.

Introduction / Context:
This sentence improvement question examines parallelism and correct use of auxiliary verbs in a correlative structure. The sentence uses the construction "will not just A but B" to talk about the effect of a beautiful landscape. The bracketed phrase "fill us" must be checked to see whether it needs an auxiliary verb for full parallel structure with "will ... attract."

Given Data / Assumptions:

• The first part of the verb phrase is "will not just attract our attention."
• The second part is "but (fill us) with infinite satisfaction."
• The subject for both actions is "A beautiful landscape."
• The tense and modality should remain consistent across both parts.

Concept / Approach:
Correlative patterns like "not just ... but also ..." typically maintain the same auxiliary verb structure in both parts. Since the first part uses "will" in "will not just attract," the second part should logically use "will" as well, giving "but will fill us." Omitting "will" in the second part can be acceptable in some informal contexts, but for exam standard and clear parallelism, including "will" is preferred.

Step-by-Step Solution:
Step 1: Identify the auxiliary verb in the first part of the sentence. It is "will." Step 2: Recognise that the second part of the sentence shares the same subject and should match the tense and modality. Step 3: Add "will" before "fill us" to mirror the structure "will attract." Step 4: Form the improved phrase "will fill us." Step 5: Read the entire sentence: "A beautiful landscape, full of green vegetation, will not just attract our attention but will fill us with infinite satisfaction." This now exhibits clear parallel structure and consistent tense.

Verification / Alternative check:
Check against similar examples: "The new policy will not just reduce costs but will improve efficiency," or "The programme will not just inform you but will inspire you." In both cases, "will" appears in each part to maintain symmetry and clarity. Using the same pattern here confirms that "will fill us" is the most appropriate phrasing.

Why Other Options Are Wrong:
Option B: "filled us" switches to past tense and breaks the future orientation of the sentence, which is set by "will not just attract." Option C: "fill them" wrongly changes the object pronoun from "us" to "them," which is inconsistent with the earlier "our attention." Option D: "No improvement" is not ideal because omitting the auxiliary "will" after "but" weakens the parallel structure and is not the formal standard expected in exam questions.

Common Pitfalls:
Students sometimes ignore the need for parallel structure in correlative conjunctions. They may think that repeating the auxiliary is unnecessary or redundant. However, in formal written English, especially in examinations, repeating the auxiliary in the second part of a "not just ... but also ..." structure often makes the sentence clearer and stylistically better. Maintaining parallelism helps the reader see that both actions are of equal importance and share the same subject and tense.

Final Answer:
The correct improvement is "will fill us," so the sentence should read: A beautiful landscape, full of green vegetation, will not just attract our attention but will fill us with infinite satisfaction.