Were they emptying the washing machine when you came home?
Yes, they were.
Was she reading a newspaper?
No, she wasn't.
Was she making pizza when you came home?
No, she wasn't.
Were they working on the computer at noon?
Yes, they were.
Was he making breakfast at 8:00 last Sunday?
No, he wasn't.
Was she talking on the phone this morning?
Yes, she was.
Were they watching TV yesterday evening?
Yes, they were.
Was she doing the dishes yesterday morning?
Yes, she was.
Was he working on the computer after his workout?
No, he wasn't.
Was she walking the dog at 7 am?
Yes, she was.