Modal verbs+ past participle

Why were there no buses yesterday? Maybe it was the snow or they _____ been on strike.

• must have

• might have

• couldn't have

You _____ seen her, surely! She was standing right in front of you.

• must have

• might have

• can't have

Let's ask at reception to see if they have your keys. Someone _____ found them.

• can't have

• might have

• must have

He _____ gone to Russia. He didn't have a passport.

• must have

• might have

• couldn't have

I explained the homework but she did the wrong page. She _____ misunderstood me for sure.

• must have

• may have

• can't have

Oh no! My phone's not in my bag. I _____ left it at home.

• must have

• couldn't have

• can have

It is still a mystery how the robber gained access to the bank. Police are investigating whether the suspect _____ known one of the employees.

• must have

• may have

• couldn't have

I _____ left my wallet in the restaurant. I paid for the taxi home afterwards.

• must have

• could have

• can't have

Where's Clare? Her bag's here and her computer's still on so she _____ gone home.

• must have

• might have

• can't have

I can't remember my password! But I _____ written it in my notebook as sometimes I do that.

• must have

• may have

• couldn't have