Degrees of certainty

Many accidents could\ must\ can be prevented with a little care.

She is down in the dumps. She MUST \ CAN'T \ MAY have broken up with her partner.

The road is wet. It can't have been raining\must be raining\must have been raining.

Our car broke down and we couldn't \ may not have enough money to pay for the repairs.

Her new car looks expensive. It must hace cost\ mus cost\ can't have cost a fortune.

He didn't answer the phone. He CAN'T HAVE BEEN \ MUST HAVE BEEN SLEEPING sleeping.

They might\can't\should have gone home. I don't see him anywhere.

You have to\ should be joking. He can't have \ might not have passed away. I saw him on TV just now.

They're going whitewater rafting. They have to\ may be mad to do such a thing!

You can't be hungry\must be hungry\ should be hungry. You've only just had lunch.

Surely he mustn't\can't still be alive after all this time.

I don't know where Bernard is - he must\could be playing tennis with Carrie.

She couldn't \ might not want to come with us.

Mr. Morris must \ can't be nearly years old but he doesn't look it.