The past continuous (sometimes called the past progressive) is a tense that’s used to describe an action or event that was ongoing in the past moment being referenced.
Formed by combining the simple past of the verb to be (i.e. was or were) with the present participle of the main verb, the past continuous is constructed thusly:
I was trying.
It was stinging.
They were typing.
The past continuous can also be formed using the present participle of a multi-word or phrasal verb, where the main verb of the phrase is in continuous form:
She was giving up.
In both spoken and written forms of English, the past continuous is commonly used to describe one past action or event in relation to another, for example to indicate the separation of two events, or an ongoing action in the past:
Separation of Two Events
When one action is interrupted by another, the past continuous is normally used, where the first action is formed by the past continuous and the second by the simple past.
In the examples below, the past continuous is indicated in bold and the simple past is indicated with an underline:
The postman was finishing his deliveries when the wind picked up.
She was negotiating a pay raise when I walked in on her.
Similarly, the past continuous is used when two actions occur simultaneously:
While the guitarists were setting up, the electricity tripped.
Ongoing Action
The past continuous is also frequently used to describe a habitual action in the past which occurred over a longer period of time in an ongoing or repetitive manner:
We were seeing signs that change was in the air.
I was fishing every Sunday during my twenties.
Recommended Read
Ilse Depraetere & Chad Langford, Advanced English Grammar: A Linguistic Approach. Bloomsbury Academic, 2019. See the book