---Your aunt often walks a dog in the morning. ---Yes, bad weather stops her.
We were deeply impressed by the schools ______ we had visited in this city.
—What should I do, doctor? —You should take more exercise ______ healthy.
—Maggie, why did you take a bus today? —Oh, I forgot to tell you about that. My bicycle ______ yesterday.
—Someone is knocking at the door. Who ______ it be? —It ______ be Victor. He went to London yesterday.
When the firemen arrived, the fire had been ______