Ответ:
1 Were they walking along the street at this time yesterday?
Were they walking along the street or in the park at this time yesterday?
Were they walking along the street at this time yesterday, weren't they?
What were they doing at this time yesterday?
Who were walking along the street at this time yesterday?
2 Did a cat catch a little mouse five minutes ago?
Did a cat catch a little mouse or a butterfly five minutes ago?
Did a cat catch a little mouse five minutes ago, didn't it?
When did a cat catch a little mouse?
Who caught a little mouse five minutes ago?