in the kitchen / I saw you / were you eating / when / What / ?
What were you eating when I saw you in the kitchen?
He never went out with his friends because he was training. (used to)
He didn't use to go out with his friends because he was training.
He won a lot of matches when he was young. (used to)
He used to win a lot of matches when he was young.
I fell and broke my arm...
when I play tennis.
when I was playing tennis.
