In the sentence The citadel of our cultural heritage has come under the _____ of Western culture, choose the word that best completes the blank.

Introduction / Context:
This vocabulary in context question focuses on choosing a word that correctly expresses influence or control. The phrase under the _____ of Western culture must be completed with a noun that can naturally collocate with under the and suggest dominance or influence.

Given Data / Assumptions:
• The sentence speaks about Western culture affecting our cultural heritage.
• Under the blank must form a meaningful phrase with Western culture.
• The intended meaning is influence, dominance, or control rather than simple physical movement.
• Only one option should fit both grammatically and semantically.

Concept / Approach:
The key concept is the fixed expression under the sway of, which means under the influence or control of something or someone. This is a common phrase in English used in political, cultural and psychological contexts. We compare each option for collocation and meaning to see which one fits best.

Step-by-Step Solution:
Step 1: Identify the core idea that Western culture influences or dominates our cultural heritage. Step 2: Recall common idiomatic expressions that follow the pattern under the _____ of. Step 3: Recognise that under the sway of is a standard phrase meaning under the influence of. Step 4: Insert sway into the sentence to check that it reads smoothly and conveys the intended meaning. Step 5: Check that tide, current and wind do not form standard, idiomatic expressions in this cultural context.

Verification / Alternative check:
Test each option in the sentence: under the tide of Western culture, under the current of Western culture, under the wind of Western culture, under the sway of Western culture. Only under the sway of Western culture is a recognised idiom that clearly means under the influence of Western culture.

Why Other Options Are Wrong:
Tide: Under the tide of is not a standard phrase, and tide suggests a physical flow of water rather than cultural influence.
Current: This applies to water or electricity; under the current of sounds awkward and does not convey the idea of control or influence clearly.
Wind: Under the wind of has no idiomatic meaning, and wind does not express cultural domination.

Common Pitfalls:
Students sometimes pick tide or current because they imagine Western culture moving like a wave. However, the exam expects you to recognise the exact idiomatic expression under the sway of, which directly matches influence in the context of culture and ideas.

Final Answer:
The correct answer is sway because the phrase under the sway of Western culture is an established idiom meaning that our cultural heritage has come under its powerful influence.