—Perhaps John's not in.—______.Look,the light's on.
—Isn’t that Ann’s husband over there? —No, it _______ be him—I’m sure he doesn’t wear glasses.
We hope that as many as possible _______ join us for the picnic tomorrow.
—I seldom watch TV, but listen to the radio a lot. —_______.
Only _______ to borrow magazines from the reading-room.
Those who know _______ it was that wrote A Tale of Two Cities, raise your hands.