Idiomatic Collocation – Choose the option that BEST explains the highlighted phrase. Sentence: “He did me a good turn by recommending me for the post of Vice Principal.”

Introduction / Context:
“Do someone a good turn” is a fixed English collocation meaning to do someone a favor or kind action. The sentence directly names the favor: recommending a person for a post. The phrase is neutral about reciprocity; it need not be a return favor.

Given Data / Assumptions:

• Highlighted phrase: “did me a good turn”.
• Example of the favor: recommendation for a role.
• We must select the closest paraphrase.

Concept / Approach:
Among options, “did an act of kindness” exactly matches the collocation. “Returned my kindness” adds an unnecessary notion of repayment; “improved my prospects” is a result, not the idiom’s meaning; “became suddenly good” is incorrect.

Step-by-Step Solution:
Define expression: a good turn = a favor.Relate to context: recommendation is indeed a favor.Choose “did an act of kindness.”

Verification / Alternative check:
Substitute: “He did me a favor by recommending me …” The sentence remains precise.

Why Other Options Are Wrong:

• returned my kindness: implies earlier kindness; not stated.
• improved my prospects: describes effect, not idiomatic meaning.
• became suddenly good: not the sense of “good turn.”

Common Pitfalls:
Confusing meaning with outcome; the idiom labels the action itself as a favor.

Final Answer:
did an act of kindness