In their efforts to persuade us to buy that product, shopkeepers have made a close study of human nature and have_______ all our little weaknesses.
Was it _____ she heard with her ears _____ really made her frightened?
Is this factory _____ you visited the other day?
Never _____ time come back again.
Can _____ be in the desk _____ you have put my letter?
Time should be made good use of ____ our lessons well.