The Simple Past is used to describe a completed action at a specific time in the past and the Past Continuous is used to describe an action in progress at a specific time in the past.
In other words, something was happening, and was interrupted by another event. The thing that was happening uses the Past Continuous, and the thing that interrupted uses the Simple Past.
Two main ways that Simple Past and Past Continuous are used are shown in the following sentence patterns:
1. When ….V (simple past), S V (past continuous). // S V (past continuous) when ….V (simple past)
When the phone rang, we were eating. // We were eating when the phone rang.
When the baby woke up, I was writing a letter. // I was writing a letter when the baby woke up.
Note: Using this form emphasizes the interruption.
2. While ….V (past continuous), S V (simple past). // S V (simple past) While ….V (past continuous)
While we were eating, the phone rang. // The phone rang while we were eating.
While I was writing a letter, the baby woke up. // The baby woke up while I was writing a letter.
Note: Using this form emphasizes the action that was in progress.
Here, using Simple Past for both clauses indicates cause and effect – one thing happening leads to another. You can think of “when” as being the same as “after” in this case.
When the alarm went off, I got out of bed. // I got out of bed when the alarm went off.
(After the alarm went off, I got out of bed. // I got out of bed after the alarm went off.)
When the light bulb burned out, he replaced it. // He replaced the light bulb when it burned out.
(After the light bulb burned out, he replaced it. // He replaced the light bulb after it burned out.)
Simple Past: used to describe permanent states, completed actions in the past, or actions completed during the specified time period.
We waited for an hour. (completed action)
The house burned down. (completed action, permanent situation)
I took piano lessons. (completed action)
It snowed yesterday. (only part of the day)
Past Continuous: used to describe temporary states, incomplete actions in the past, or actions in progress during the specified time period.
It was snowing yesterday. (whole day)
We were digging in the garden yesterday afternoon. (in progress)
Exercises: Put the verb in the past continuous or simple past.
What (you / do) when the lights (go) out? (“go out” = lose electrical power) ==> What were you doing when the lights went out?
I (do) homework. ==> I was doing homework.
1. Who (ring) the doorbell? It (be) a girl scout. She (sell) cookies.
2. What (you / do) yesterday? We (paint) the bedroom.
3. What (you / do) last night? I (do) laundry.
4. (Mary / come) to the party last Friday? No, she (study) for the test all evening.
5. When (you / study) for the test? I (study) while I (ride) the bus to school.
6. The phone (ring) while I (take) a bath.
7. It (start) to rain when we (take) a walk.
8. When Henry (come) home, he (skip) supper and (go) to bed.
9. After Susan (eat) breakfast, she (leave) for school.
10. The choir (sing) when the photographer (take) the picture.