I'm sure that Liz hasn't met Harry before. Liz ...
Liz can't have met Harry before.
I'm sure that Harry feels lonely. Harry....
Harry must feel really lonely.
Jack is late! He was supposed to have arrived half an hour ago. Jack ...
Jack should have arrived half an hour ago.
Mary knows how to stand on her head. Mary ...
Mary can stand on her head.
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!
Perhaps Pam and Tim decided not to come. Pam and Tim ....
Pam and Tim might/may/could have decided not to come.
It was a waste of time worrying, after all! You ....
You needn't have worried after all!
It was unnecessary for you to clean the floor. You....
You needn't have cleaned the floor.
I'm sure that David took your books by mistake. David ....
David must have taken your books by mistake.
I'm sure that Brenda isn't over thirty. Brenda.....
Brenda can't be over thirty.
What would you advise me to do? (think)
What do you think I should do?
I'm sure they haven't eaten all the food. It's not possible! They ....
They can't have eaten all the food.
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 it was the cat that took the fish from the table! The cat .....
The cat must have taken the fish from the table.
Heather possibly hasn't left yet. Heather...
Heather might not have left yet.
You're not allowed to park here. You .........
You can't / mustn't park here.