In our school library, there a very small number of books on history, and in these years the mumber of them getting larger and larger.
--- I feel tired and sleepy. --- Why not stop ______?
--- Betty, could you answer my question? --- Sorry, Mr. Green. I didn’t hear you. I _______ about something else.
--- I won’t have time to go shopping with you this afternoon. --- But you ________ me yesterday.
His father often tells him _______ in that river because it’s dangerous.
--- The office isn’t _______. Will you please turn on the lights? --- Sure.