—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
Why haven't you finished your homework yet? You___________ to have finished it by last Sunday.
Could you give me a hand __________from the car, please?
--I'm told that John had another car accident this morning.--I believe not. He _________so careless.
The Bunsen Burner is so named because it is thought ___________ by Robert Bunsen.
--I didn't know this was a one-way street, officer.