The past continuous tense, also known as the past progressive tense, refers to a continuing action or state that was happening at some point in the past. The past continuous tense is formed by combining the past tense of to be (i.e., was/were) with the verb’s present participle (-ing word).
There are many situations in which this verb tense might be used in a sentence. For example, it is often used to describe conditions that existed in the past.
It can also be used to describe something that was happening continuously in the past when another action interrupted it.
The past continuous can shed light on what was happening at a precise time in the past.
It can also refer to a habitual action in the past.
One final caution: Though the irregularities are few, not every verb is suited to describing a continuous action. Certain verbs can’t be used in the past continuous tense. One common example is the verb to arrive.