Past Simple: Did you watch the movie last night?
Past Progressive: What were you doing when I called you yesterday?

Past Simple: Where did you go on vacation last summer?
Past Progressive: What were you thinking about when you suddenly started laughing?

Past Simple: Did you finish your homework before dinner?
Past Progressive: What were you studying when the power went out?

Past Simple: What did you eat for breakfast this morning?
Past Progressive: What were you cooking when I came into the kitchen?

Past Simple: Did you play any sports in high school?
Past Progressive: What were you wearing when you ran into your ex-boyfriend?

Past Simple: How did you get to work yesterday?
Past Progressive: What were you listening to on your way to the office?

Past Simple: Did you go shopping for groceries last weekend?
Past Progressive: What were you buying when you bumped into your neighbor at the store?

Past Simple: Did you have a good time at the party last night?
Past Progressive: What were you doing when the music suddenly stopped?