1.
Did he refuse to take this offer?
Did
he refuse to take or accept this offer?
What
offer did he refuse to take?
He
refused to take this offer, didn't he?
Who
refused to take this offer?
2.
Were they having supper at 9?
Were
they having supper at 9 or at 10?
What
were they doing at 9?
They
were having supper at 9, weren't they?
Who
was having supper at 9?