Perhaps he is at school today.
He may be at school today. (might / could)
Kate is shivering. She ------------- be cold.
must
I'm sure that Susan is not the thief.
Susan can't be the thief.
It is impossible that he is Spanish.
He can't be Spanish.
It is possible that you left your wallet at home.
You might have left your wallet at home. (may)
I'm sure Juan isn't Irish.
Juan can't be Irish.
I had an umbrella when I came out but I haven't got it now.You (leave) ------------- it on the bus.
might / may / must have left (may )
Did you hear me come in last night? No, I (be) -----asleep.
must have been
Emily is crying. She --------------- be sad.
must
I’m certain that she is a doctor.
She must be a doctor.
Perhaps he left the gate open.
He might have left the gate open. (may)
Perhaps he was at home yesterday.
He might have been at home. (may/could)
I'm sure you forgot to do your homework.
You must have forgotten to do your homework.
I'm sure she is at home today.
She must be at home today.
John will probably come to the party. John...
John may come to the party. (might / could)
I'm sure they aren't at work today.
They can't be at work today.
I'm sure the cat is in the house somewhere.
The cat must be at home (in the house)