Past Progressive (Continuous)

 An action over a past period

We use the past continuous for an action over a period of past time, something

that we were in the middle of.

At quarter to eleven I was walking home.

The UFO was travelling east to west.

I wasn't sleeping, so I got up.

I looked into the room. All the old people were watching television.

Compare the present continuous and past continuous.

The UFO is travelling west. (It is in the middle of its journey.)

The UFO was travelling west. (It was in the middle of its journey.)

But for a complete action in the past, we use the past simple.

The UFO went behind a cloud.

In these examples the past continuous means an action over a whole period.

The salesman was travelling from Monday to Friday.

We were watching for UFOs all night. We never went to sleep.

Here we could also use the past simple.

Period of time: He was travelling all week. He was very tired.

Complete action: He travelled all week. He drove a long way.

b Past continuous and past simple

The period of a past continuous action can include a clock time.

/ was walking home at quarter to eleven.

It can also include another action.

/ was walking home when I saw the UFO.

Here the speaker sees one action as happening around another. The past

continuous is the longer, background action (walking), and the past simple is the

shorter, complete action (saw). The shorter action interrupted the longer one.

Here are some more examples.

Tim was washing his hair when the doorbell rang.

I had a sudden idea when/while/as I was waiting in a traffic queue.

The sun was shining when the campers woke.

When two actions both went on during the same period of time, we use the past

continuous for both.

Tim was washing his hair while I was cleaning up the kitchen.