In the nuclear security passage, select the noun that best completes the sentence: "the summits narrowed their ___________ to civilian holdings".

Introduction / Context:
This question is a vocabulary and collocation test based on a passage describing nuclear security summits. It asks you to choose the most appropriate noun to complete the phrase "the summits narrowed their ___________ to civilian holdings". The expression must sound natural in academic and policy writing and convey the idea of limiting the scope of discussion.

Given Data / Assumptions:

• The clause is: "the summits narrowed their ___________ to civilian holdings".
• Options are: view, focus, attention, vision, priority.
• The wider passage contrasts broad declarations with a narrow practical emphasis.
• We must choose the noun that collocates naturally with "narrowed their".

Concept / Approach:
In English, certain verbs and nouns frequently appear together. The phrase "narrow one's focus" is very common and means to limit the range of issues considered. While "view" and "attention" are also used with "narrow", the most common formal collocation in policy discussions is "narrowed their focus". Recognising these patterns is important for reading comprehension and precise writing.

Step-by-Step Solution:
Step 1: Understand that the summits are being criticised for limiting what they concentrated on. Step 2: Recall the common expression "narrow their focus", which means to reduce the range of topics being considered. Step 3: Insert "focus" into the sentence: "the summits narrowed their focus to civilian holdings". This reads smoothly and clearly conveys that the scope of concern was limited. Step 4: Try "view" in the sentence: "narrowed their view to civilian holdings" sounds less natural and could imply narrowing perspective, but is not the standard expression in policy writing. Step 5: Test "attention": "narrowed their attention to civilian holdings" is possible but less idiomatic in this formal context. Step 6: "Vision" usually refers to long term plans or imagination, and "narrowed their vision" sounds stylistic but does not fit as well as "focus". Step 7: "Priority" is not something usually "narrowed"; instead, priorities are set or changed. Step 8: Therefore, "focus" is the best answer because it forms the most natural and widely recognised collocation.

Verification / Alternative check:
You can check by thinking of other phrases: "The committee narrowed its focus to three key issues" is a very common pattern. In contrast, "narrowed its view" or "narrowed its attention" are less frequent and sound stylistically weaker. Policy documents and analytical essays regularly use "narrowed focus" to describe this kind of limitation, supporting your choice.

Why Other Options Are Wrong:

• view: Could theoretically work, but "narrowed their view" is not the typical policy collocation here.
• attention: Grammatically right but stylistically less preferred than "focus" in formal analytical writing.
• vision: Usually used to talk about long term plans and imagination, not about limiting the scope of active concern in summits.
• priority: You can "set priorities" or "change priorities", but "narrow their priority" is not standard usage.

Common Pitfalls:
Students may sometimes select any noun that seems related to thinking or looking without considering collocation strength. Another pitfall is ignoring the formal tone of the passage and treating the sentence like casual speech. To improve, pay attention to how phrases like "focus", "scope", and "agenda" are used in editorials and reports, since exam authors draw heavily from that style.

Final Answer:
The correct noun to complete the sentence is focus.