When the President came to visit our school, the Headmaster taught there for ten years.
When the President came to visit our school, the Headmaster taught there for ten years.
When the President came to visit our school, the Headmaster had taught there for ten years.
When the President came to visit our school, the Headmaster had taught there for ten years.
When the President came to visit our school, the Headmaster had been teaching there for ten years.
When the President came to visit our school, the Headmaster had been teaching there for ten years.
When the President came to visit our school, the Headmaster has been teaching there for ten years.
When the President came to visit our school, the Headmaster has been teaching there for ten years.
Correct Answer:
When the President came to visit our school, the Headmaster had been teaching there for ten years.