That children ______meet with setbacks is a matter of necessity as they_____, so parents don’t worry about that.

I'm afraid Mr.Harding ______ see you now.He's busy.

There is a “ No smoking “ sign here. You _________ smoke.

The light is on in Mr. Green’s room. He _______ be at home.

—Isn’t that Ann’s husband over there?—No, it ______ be him-I’m sure he doesn’t wear glasses.