OPG It may/could/must have been, etc.

► Rita: Tom’s car was stolen. He hadn’t locked it.
     David: I suppose it’s his fault then. He should have locked it.

► Tom: I can’t sleep sometimes. My neighbours play music all night.
     Melanie: That’s a nuisance. They shouldn’t play music all night.

1- Mark: The picnickers left litter everywhere.
    Sarah: That’s awful.

2- Emma: Jessica isn’t very friendly, is she? She never says hello to people.
     Matthew: I know.

3- Rachel: I don’t think Daniel’s going to get that job. He was late for the interview.
    Natasha: That can’t have looked very good.

4- Daniel: Did you see Vicky crossing the road? She didn’t look.
     Emma: She could have been killed.

Harriet: There’s a parcel outside. The postman must have left (leave) it.

Mike: Well, (he/ leave) it outside. He isn’t supposed to do that. Someone (take) it. Why didn’t he ring the bell?

Harriet: He always rings. (you / be) out when he came.

Mike: I haven’t been out. So (he / ring) the bell.

► Matthew: I’m sure the computer didn’t make a mistake. That’s impossible.
Emma: No, of course the computer couldn’t have made a mistake.

1- Mark: I can’t see the letter here now. So clearly someone posted it.
Alan: Yes,

2- Natasha: It’s possible Emma didn’t hear the alarm.
Rachel: Well, I suppose

3- Sarah: Henry drove at 100 miles an hour. Don’t you think that’s dangerous?
Mark: Yes, I do.

4- Daniel: I just don’t believe that Andrew has failed the exam.
Vicky: Andrew? Impossible!