Past Progressive

1.We form the Past Progressive in this way:

POSITIVE
I/he/she/it	was	waiting.
You/we/they	were	waiting.

NEGATIVE
I/he/she/it	was not/wasn't	waiting.
You/we/they	were not/weren't	waiting.

QUESTIONS
Was	I/he/she/it	waiting?
Were	you/we/they	waiting?

2. Look at this example:

A: What were you doing at 7 o'clock last night?

B: I was driving home from work.

I was living in Japan in 1991. (I lived there from 1990 to 1993.)

We use the Past Progressive for an action or situation that was in progress at a particular time in the past (e.g. at 7 p.m., in 1991).

3. Now look at this:

When I walked into the room, Ann was writing postcards and Keith was reading.

We use the Past Simple (walked) for a completed action. We use the Past Continuous (was writing) for an action in progress in the past.

4. We can use when or while before the Past Continuous:

I met her when/while we were working for the same company. (when = during the time)

We can only use when (not while ) before the Past Simple:

When I met her, we were working for the same company. (when = at the time)"

Other source

• English Page - Past Continuous
• Ginger - Past Progressive