------ May I smoke here?------ If you____, that's the smoking section over there.

----I am really surprised that a policeman in his car __________ have hit several common pedestrians, killing one and injuring three.----Yes, If one __________ ask for trouble, what can we say?

Curious about the world around him, my son__   __ask me endless questions when he was young．

–Will you read me a story, Mummy? --OK. You ______have one if you go to bed as soon as possible.

 --- Do we have to hand in our research reports this afternoon, Professor Smith?--- Yes, you _______ . I will be waiting to check them all the afternoon.