Difficulty: Easy
Correct Answer: walked
Explanation:
Given data
Concept/Approach
Use the simple past for habitual actions in a finished past period.
Option analysis
walked — correct simple past for a finished past habit.had walked — past perfect; requires a later past reference point.have walked / have been walking — present perfect forms; incompatible with the finished past time marker.
Common pitfalls
Overusing present perfect with clear past-time expressions (e.g., “when I was a child”).
Final Answer
walked
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