—Who______ it be that is knocking at the door?—It ______ be Father, but I’m not sure.A. can; must B. can; may . must; can D. may; must
No one can avoid ______ by advertising; it is everywhere.
With all the audience ________, the speech began.
—Ken, why do you look so tired? —I _______ myself to the climate since I came here.
Some passers-by witnessed the car accident____ five passengers were killed, a baby included.
The girl got nothing in ______ for her kindness, which made her very sad.