--Listen! Is it Linda singing in the next room? --No, it __________ be her. She is still in Shanghai.
We should prevent the children ________ the bad programmes.
The Olympics ________ every four years. And the 29th Olympics ________ in Beijing in 2008.
I think ________ necessary ________ to take more exercise.
A football match ________ in our school next Monday.
We will spend our winter holiday in Shanghai, but we haven’t decided _______.