Traffic restrictions have come into effect in Beijing to improve thecapital’s air quality and traffic situation for the 2008 Olympics

_____ I’m hungry, _____ I have some food.

If you buy ________ MP4 player in our store, you can get a watch for ________ free.

My father used to to work on foot, but now he is used to to work by bike.

He __________ hisaunt’s when he went to Wuhan on business.