Past Continuous: was happening then

Now move the same idea into the past. Everything stays the same, except the helper changes to was or were.

Compare. I am walking, happening now. I was walking, happening at some point in the past. Same building, new helper.

I was, he was, she was, it was. You were, we were, they were. Listen to it: they was sounds wrong, and it is wrong.

Here is the best use of it. We were watching the match when the power went out. The watching was long and ongoing. The power going out was short and sudden. Long action in past continuous, short action in simple past.

So the choice is simple. Happening now, use am is are. Happening then, use was or were. Ask yourself one question: when did this happen? The answer picks your helper.

You can now build was and were plus verb ing, tell the present from the past continuous, and use it to show an interruption. Practise it now.