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.
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.