By the time mum came home her son had notcooked the dinner.
Who had cooked the dinner by the time mum came home?
Sandra had not been writing a report for three hours before she did not realize it was too late.
Who had been writing a report for three hours before she realized it was too late?
This bridge was not built in 1953.
When did this bridge was built?
Tom was not reading a very interesting book while his dad was not watching a football match.
Who was reading a very interesting book while his dad was watching a football match?