Do you have to ____ your little sister this Sunday?
Could you tell me_____?
The_______ you are in the exam, the_______ mistakes you will make.
-- are the Olympic Games held? --Every four years.
--Is this kite ________? --No, it’s mine. It’s made by ________.
--When did the World Exposition(世博会) in Shanghai begin? --The Expo began ________ May 1, 2010.