—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
You might as well ___ him alone no matter what he will say.
They all agreed ___ what you said at the conference.
I’m afraid I can’t take down what you’ve just ___.
America belongs to the ___country while China and India are both ___countries.
The teacher asked us to ___ Lesson Ten if we hadn't finished it.