—Have you checked the engine? —Yes, I did twice; there ______ be anything wrong with the car.

Food safety is important. Rules        to stop people from food pollution.

— Who _____ be phoning us at this time of night? — It might be your sister. 

—Is it necessary to look up every new word when I come across it in reading?—No. You ________， because you are likely to guess the meaning from the context.

---I can’t stop playing computer games. --For your eyes,my boy,I’m afraid you______.