CORRECT: He mustn’t have gone home; his jacket is on the back of his chair.

I regret not saving my documents before I switched off the computer. - OUGHT - I ______ my documents before I switched off the computer

You could /needn’t have borrowed my car to go to the interview. I wasn’t using it.

John mustn't / wouldn't have applied for the job if he had known it wasn’t permanent.

It wasn’t necessary for Bill to wear a tie to the interview. Nobody else did. - HAVE - Bill ______ a tie to the interview as nobody else did.

You can't / must have had a hard day at work. You look really tired.

You should / can have listened to the lecturer; he was very good.

CORRECT: If you hadn’t been late, you mustn’t have been given the sack.

I wouldn't / should have asked the manager about doing overtime when he was here.

It was a bad idea to wear your jeans to the interview. - SHOULD - You ______ your jeans to the interview.

Terry can’t / needn’t have arrived yet, he only left two minutes ago!

I’m sure you haven’t lost your keys. You had them two minutes ago. - HAVE - You ______ your keys. You had them two minutes ago.

I can / needn't have taken my CV to the interview after all. The interviewer had a copy.