It was unnecessary for you to clean the floor. You....
You needn't have cleaned the floor.
Perhaps Pam and Tim decided not to come. Pam and Tim ....
Pam and Tim might have decided not to come.
It was a mistake to park outside the police station. You ....
You shouldn't have parked outside the police station.
It's possible for anyone to break into this house! Anybody .....
Anybody can / could break into this house!
I think it was the cat that took the fish from the table! The cat .....
The cat must have taken the fish from the table.
I'm sure they haven't eaten all the food. It's not possible! They ....
They can't have eaten all the food.
What would you advise me to do? (think)
What do you think I should do?
I'm sure that Helen feels lonely. Helen.....
Helen must feel really lonely.
The dentist will see you soon. I don't think he'll be long. // The dentist will see you soon. He .....
He shouldn't be long.
Heather possibly hasn't left yet. Heather...
Heather might not have left yet.
You needn't come with me if you don't want to. You .....
You don't have to come with me if you don't want to.
I'm sure that David took your books by mistake. David ....
David must have taken your books by mistake.
You're not allowed to park here. You .........
You can't / mustn't park here.
It would be a great idea if Harry took a holiday. Harry ....
Harry should take a holiday.
Mary knows how to stand on her head. Mary ...
Mary can stand on her head.
I'm sure that Brenda isn't over thirty. Brenda.....
Brenda can't be over thirty.
Jack is supposed to have arrived half an hour ago. Jack ...
Jack should have arrived half an hour ago.
Do I need a different driving licence for a motorbike? Do I ......
Do I have to have a different driving licence for a motorbike?
I'm sure that Liz hasn't met Harry before. Liz ...
Liz can't have met Harry before.