—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
. If you can’t settle the dispute by yourselves, I’ll call the police and they’ll ______.
_______ to wait a long time at the dentist’s, Mike decided to take along a magazine to read.
—We need someone to design the new art museum for us.—_______ the young fellow have a try?
Sorry, these two tables are already ______. You may book the one over there.
—You see, I’m poor in physics and you are not good at chemistry, and…… — That’s _______ we should help each other.A. when B where C. how D. what