past simple vs past continuous

I can't decide between past simple and past continuous in the following sentences.

1. Queen Victoria ruled / was ruling more than a hundred years ago.

2. He read / was reading a lot when he was a student.

3. I prepared / was preparing for the report for a whole hour yesterday.


It looks either of them is possible, but there must be some difference in how the event is pictured. What is it?

1. Queen Victoria ruled more than a hundred years ago.

2. He read a lot when he was a student.

3. I prepared / was preparing for the report for a whole hour yesterday.

• Present Simple = fact
• Continuous, Be -ing + TIME (i.e., ... when ... / At the time, ..., etc.)