Re-write the sentences so that they have the same meaning as the original. You must use a modal verb.
I'm sure John locked the office before leaving. He always does.
If I were you I would tell him the truth.
It isn't necessary for her to phone me back.
Ann finished the project on her own although it wasn't necessary to do so.
It was a mistake to sell the house. I wish I hadn't.
Perhaps we'll go swimming tomorrow.
I think Mary is probably at home because the windows are open.
Perhaps John knew about the trip, but I'm not sure.
I'm sure he didn't lock the door. He never does.
Perhaps she was at work when the earthquake struck.
© Olga Godoy Giménez, 2002