Past Continuous

This tense was formed using two components: the verb BE (in the past tense), and the -ING form of a verb. Here are the rules, using the example verb "sing":

Subject	BE	-ING Form
I	was	singing
You	were	singing
He	was	singing
She	was	singing
It	was	singing
We	were	singing
They	were	singing

The past continuous is usually used when one action began before another, and finished after it. Consider this sentence:

I was reading when he arrived.

In other words I started reading (maybe at 8 o'clock), then he arrived (maybe at 9 o'clock), then I finished reading (maybe at 10 o'clock). Here is a diagram:

We can also use the tense when we talk about an action that had already started and was still continuing at a particular time:

At five o'clock, it was raining.

In other words it started raining (maybe at 4 o'clock), and finished raining later (maybe at 6 o'clock). Here is a diagram:

Finally, we can use this tense to describe TWO actions that were BOTH continuing at the same time in the past. In this case, we use the past continuous for both actions:

While I was sleeping, she was working.

In other words I started sleeping and she started working (maybe at 10 o'clock), and we both finished our actions later (maybe at 12 o'clock). Here is a diagram: